umu.sePublications
Change search
Refine search result
123 51 - 100 of 102
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 51.
    Malisauskas, Mantas
    et al.
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Weise, Christoph
    Umeå University, Faculty of Science and Technology, Department of Chemistry. Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Yanamandra, Kiran
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Wolf-Watz, Magnus
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Morozova-Roche, Ludmilla
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Lability landscape and protease resistance of human insulin amyloid: a new insight into its molecular properties2010In: Journal of Molecular Biology, ISSN 0022-2836, E-ISSN 1089-8638, Vol. 396, no 1, p. 60-74Article in journal (Refereed)
    Abstract [en]

    Amyloid formation is a universal behavior of proteins central to many important human pathologies and industrial processes. The extreme stability of amyloids towards chemical and proteolytic degradation is an acquired property compared to the precursor proteins and is a major prerequisite for their accumulation. Here we report a study on the lability of human insulin amyloid as a function of pH and amyloid ageing. Using a range of methods such as AFM, thioflavin-T fluorescence, circular dichroism and gas phase electrophoretic mobility macromolecule analysis we probed the propensity of human insulin amyloid to propagate or dissociate in a wide span of pHs and ageing in a low concentration regime. We generated a three-dimensional amyloid lability landscape in coordinates of pH and amyloid ageing, which displays three distinctive features: (i) a maximum propensity to grow near pH 3.8 and an age corresponding the inflection point of the growth phase; (ii) an abrupt cut-off between growth and disaggregation at pH 8-10; (iii) isoclines shifted towards older age during the amyloid growth phase at pH 4-9, reflecting the greater stability of aged amyloid. Thus, lability of amyloid strongly depends on the ionization state of insulin and on the structure and maturity of amyloid fibrils. The stability of insulin amyloid towards protease K was assessed by using real-time AFM and thioflavin-T fluorescence. We estimated that amyloid fibrils can be digested both from the free ends and within the length of the fibril with a rate of ca. 4 nm/min. Our results highlight that amyloid structures, depending on solution conditions, can be less stable than commonly perceived. These results have wide implications for understanding the propagation of amyloids via a seeding mechanism as well as for understanding their natural clearance and dissociation under solution conditions unfavorable for amyloid formation in biological systems and industrial applications.

  • 52.
    Malisauskas, Mantas
    et al.
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Zamotin, Vladimir
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Jass, Jana
    Umeå University, Faculty of Science and Technology, Department of Molecular Biology (Faculty of Science and Technology).
    Noppe, Wim
    Dobson, Christopher M
    Morozova-Roche, Ludmilla
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Amyloid protofilaments from the calcium-binding protein equine lysozyme: formation of ring and linear structures depends on pH and metal ion concentration2003In: Journal of Molecular Biology, ISSN 0022-2836, E-ISSN 1089-8638, Vol. 330, no 4, p. 879-890Article in journal (Refereed)
    Abstract [en]

    The calcium-binding equine lysozyme has been found to undergo conversion into amyloid fibrils during incubation in solution at acidic pH. At pH 4.5 and 57 °C, where equine lysozyme forms a partially unfolded molten globule state, the protein forms protofilaments with a width of ca. 2 nm. In the absence of Ca2+ the protofilaments are present as annular structures with a diameter of 40–50 nm. In the presence of 10 mM CaCl2 the protofilaments of equine lysozyme are straight or curved; they can assemble into thicker threads, but they do not appear to undergo circularisation. At pH 2.0, where the protein is more destabilised compared to pH 4.5, fibril formation occurs at 37 °C and 57 °C. At pH 2.0, both ring-shaped and linear protofilaments are formed, in which periodic repeats of ca 35 nm can be distinguished clearly. The rings constitute about 10% of all fibrillar species under these conditions and they are characterised by a larger diameter of 70–80 nm. All the structures bind Congo red and thioflavine T in a manner similar to fibrils associated with a variety of amyloid diseases. At pH 2.0, fibril formation is accompanied by some acidic hydrolysis, producing specific fragmentation of the protein, leading to the accumulation of two peptides in particular, consisting of residues 1–80 and 54–125. At the initial stages of incubation, however, full-length equine lysozyme represents the dominant species within the fibrils. We propose that the ring-shaped structures observed here, and in the case of disease-associated proteins such as -synuclein, could be a second generic type of amyloid structure in addition to the more common linear fibrils.

  • 53. Minkevich, N. I.
    et al.
    Rakitina, T. V.
    Bogachuk, A. P.
    Radchenko, V. V.
    Surina, E. A.
    Morozova-Roche, Ludmilla A.
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Yanamandra, Kiran
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Iomdina, E. N.
    Babichenko, I. I.
    Kostanyan, I. A.
    Lipkin, V. M.
    Formation of amyloid-like fibrillar structures and destruction of fibroblasts of the Tenon's capsule in progressive myopia due to resistance of the pigment epithelium-derived factor to restricted proteolysis2012In: Russian journal of bioorganic chemistry, ISSN 1068-1620, E-ISSN 1608-330X, Vol. 38, no 6, p. 605-612Article in journal (Refereed)
    Abstract [en]

    We have previously shown that, normally, two forms of the pigment epithelium-derived factor (PEDF) with molecular weights of 50 and 45 kDa are present in the Tenon's capsule in equal amounts. These forms represent the full-length protein and a product of restricted proteolysis of PEDF. In persons with myopia, the full-length uncleaved factor was predominantly detected, which correlated with the disturbance of collagen fiber formation. An immunohistochemical study of the Tenon's capsule using polyclonal antibodies to PEDF showed that, in the control group, the factor is localized solely inside fibroblasts, whereas in patients with myopia, PEDF is distributed outside the cell as a halo around destroyed fibroblasts. It was shown in the present work using atomic force microscopy and immunodot assay with antibodies specific to amyloid fibrils that only the full-length PEDF is capable of forming amyloid-like fibrillar structures. The accumulation of fibrils leads to the destruction of fibroblasts and is a cause of changes in the biochemical composition and morphological structure of the Tenon's capsule in myopia.

  • 54. Minkevich, Natalya I.
    et al.
    Morozova-Roche, Ludmilla A.
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Iomdina, Elena N.
    Rakitina, Tatiana V.
    Bogachuk, Anna P.
    Kakuev, Dmitry L.
    Smirnova, Evgeniya V.
    Babichenko, Igor I.
    Lipkin, Valery M.
    Abnormal pigment epithelium-derived factor processing in progressive myopia2016In: Experimental Eye Research, ISSN 0014-4835, E-ISSN 1096-0007, Vol. 152, p. 1-9Article in journal (Refereed)
    Abstract [en]

    Pigment Epithelium-Derived Factor (PEDF) is a secreted glycoprotein belonging to the family of non inhibitory serpins. It is known, that in cases of complicated myopia, the content of PEDF in aqueous humor of the anterior chamber is significantly reduced. Here we examined a bulk of Tenon's capsule samples obtained from various groups of myopes, to examine PEDF processing in progressive myopia. We have analyzed the distribution of full length PEDF50 and its truncated form PEDF45 in the soluble and insoluble fractions extracted from Tenon's capsule of myopic and control (non-myopic) patients using SDS-polyacrylamide gel electrophoresis, as well as monitored the proteolytic degradation of PEDF ex vivo by enzyme-linked immunosorbent assay. These results were complemented by PEDF mRNA analysis in correspondent tissues by using qPCR and immunohistochemistry analysis of PEDF distribution in normal and myopic specimens. We found that in the Tenon's capsule of patients suffering from a high myopia the level of "soluble" 45 kDa PEDF reduced by 2-fold, while the content of "insoluble" 50 kDa form of PEDF was increased by 4-fold compared to controls. Excessive amount of PEDF50 in myopic specimens have been shown to correlate with the abrogated PEDF processing rather than with an increase of its expression. Moreover, immunohistochemical staining of the myopic Tenon's capsule tissue sections revealed the halo of deposited PEDF50 in the fibroblast extracellular space. These findings suggest that in myopia limited proteolysis of PEDF is altered or abrogated. Accumulation of full-length PEDF insoluble aggregates in the fibroblast intercellular space may affect cell survival and consequently causes the destructive changes in the extracellular matrix of the eye connective tissues. As a result, the abrogation of full-length PEDF normal processing can be an important mechanism leading to biomechanical destabilization of the scleral capsule and myopia progression.

  • 55.
    Morozova, Ludmilla A
    et al.
    Oxford Centre for Molecular Sciences, New Chemistry Laboratory, University of Oxford.
    Haynie, Donald T
    Arico-Muendel, Christopher
    Van Dael, Herman
    Dobson, Christopher M
    Structural basis of the stability of a lysozyme molten globule.1995In: Nature Structural Biology, ISSN 1072-8368, Vol. 2, no 10, p. 871-875Article in journal (Refereed)
    Abstract [en]

    Hydrogen exchange measurements on equine lysozyme show that amides in three of the four major helices of the native protein are significantly protected in a molten globule state formed at pH 2. The pattern of protection within the different helices, however, varies significantly. Examination of the pattern in the light of the native structure indicates that the side chains of the protected residues form a compact cluster within the core of the protein. We suggest that such a core is present in the molten globule state, indicating the existence of substantial native-like interactions between hydrophobic residues. The formation of clusters of this type during the early stages of folding could be crucial to directing polypeptide chains to their native structures.

  • 56.
    Morozova, Ludmilla
    et al.
    University of Leuven, Campus Kortrijk, IRC, Belgium.
    Haezebrouck, Petra
    Van Cauwelaert, Frans
    Stability of equine lysozyme: I. thermal unfolding behaviour1991In: Biophysical Chemistry, ISSN 0301-4622, E-ISSN 1873-4200, Vol. 41, no 2, p. 185-191Article in journal (Refereed)
    Abstract [en]

    The thermal denaturation of Ca(2+)- and apo-forms of equine lysozyme was followed by using far and near UV circular dichroism and intrinsic fluorescence methods. The difference found between the temperature dependence of the ellipticity at 222 nm and 287 nm, which show two stages in the thermal transition, and those at 228 nm and 294 nm, which indicate only one stage over a wide range of temperatures reflects that different subdivisions of the protein molecule are characterized by a different stability, cooperativity and pathway of denaturation. The first transition, reflected in the increase of the ellipticity at 222 nm and 287 nm, coincides with the transition detected by fluorescence and occurs at 30-50 degrees C for the apo-form and at 50-60 degrees C for the Ca(2+)-form of lysozyme. It seems to correlate with the transfer of some tryptophan residues to a more hydrophobic environment and with a local rearrangement of the tertiary and secondary structures. The unfolding transition detected by the decrease of the ellipticity at all wavelengths occurs nearly in the same temperature region for the apo- and Ca(2+)-forms, i.e. 50-80 degrees C and 55-80 degrees C, respectively. The presence of a Ca(2+)-binding loop in equine lysozyme may be partly responsible for the drastic destabilization of its structure as a whole both in the presence but especially in the absence of Ca2+ in comparison with hen and human lysozymes.

  • 57.
    Morozova-Roche, Ludmilla
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    ELOA complexes exert toxicity by targeting cullular membrance: Comparison with HAMLET2012Conference paper (Other academic)
  • 58.
    Morozova-Roche, Ludmilla
    Umeå University, Faculty of Medicine, Medical Biochemistry and Biophsyics.
    Equine lysozyme: the molecular basis of folding, self-assembly and innate amyloid toxicity.2007In: FEBS Letter, ISSN 0014-5793, Vol. 581, no 14, p. 2587-92Article in journal (Refereed)
  • 59.
    Morozova-Roche, Ludmilla
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Physico-chemical mechanisms of amyloid formation-disaggregation: in vitro and in vivo studies2010Conference paper (Refereed)
  • 60.
    Morozova-Roche, Ludmilla
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Proinflammatory S100A8/A9 in amyloid formation in the aging prostate: risk factor for cancer2016In: International Journal of Molecular Medicine, ISSN 1107-3756, E-ISSN 1791-244X, Vol. 38, p. S28-S28Article in journal (Other academic)
  • 61.
    Morozova-Roche, Ludmilla
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Pro-inflammatory S100a9 protein involved in the amyloid-neuroinflammatory cascade in Alzheimer's disease serves as a robust biomarker differentiating early stages of dementia2017In: The FEBS Journal, ISSN 1742-464X, E-ISSN 1742-4658, Vol. 284, p. 138-139Article in journal (Other academic)
  • 62.
    Morozova-Roche, Ludmilla
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Strengthening the positions of Scandinavian science in research on neurodegenerative and age-dependent amyloid diseases2010In: Amyloid: Journal of Protein Folding Disorders, ISSN 1350-6129, E-ISSN 1744-2818, Vol. 17, no 1, p. 39-Article in journal (Refereed)
  • 63.
    Morozova-Roche, Ludmilla A
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Protein misfolding and self-assembly: acquired functions and their therapeutic and pathological significance2010In: The FEBS Journal, ISSN 1742-464X, E-ISSN 1742-4658, Vol. 277, no 22, p. 4577-Article in journal (Refereed)
  • 64.
    Morozova-Roche, Ludmilla A
    et al.
    University of Oxford, Centre for Molecular Sciences, New Chemistry Laboratory.
    Arico-Muendel, C C
    Haynie, D T
    Emelyanenko, V I
    Van Dael, H
    Dobson, C M
    Structural characterisation and comparison of the native and A-states of equine lysozyme1997In: Journal of Molecular Biology, ISSN 0022-2836, E-ISSN 1089-8638, Vol. 268, no 5, p. 903-921Article in journal (Refereed)
    Abstract [en]

    Native state 1H NMR resonance assignments for 125 of the 129 residues of equine lysozyme have enabled measurement of the hydrogen exchange kinetics for over 60 backbone amide and three tryptophan indole hydrogen atoms in the native state. Native holo equine lysozyme hydrogen exchange protection factors are as large as 10(6), the most protected residues being located in elements of secondary structure. High exchange protection in the domain interface correlates with the binding of Ca2+ in this region. Equine lysozyme differs from most non-Ca2+ binding lysozymes in forming a highly populated partially folded state at low pH. The protein in this A-state at pH 2.0 has been found to bind 1-anilino-naphthalene-8-sulphonate with the enhancement of fluorescent intensity and blue shift in the spectral maximum characteristic of molten globules. NMR spectra indicate that the A-state is globally much less ordered than native equine lysozyme but does not contain significant regions of random coil structure. The amides most protected against hydrogen exchange in the A-state (protection factors up to 10(2) at 5 degrees C) correspond to residues of three of the four alpha-helices of the native state; the side-chains of these residues form a hydrophobic cluster that includes five aromatic residues. Circular dichroism and tryptophan fluorescence indicate that these residues are substantially more constrained than similar residues in "classical" molten globules. Taken together, the data suggest a model for the A-state of equine lysozyme in which a more ordered core is surrounded by a less ordered but still compact polypeptide chain.

  • 65.
    Morozova-Roche, Ludmilla A
    et al.
    Oxford Centre for Molecular Sciences, New Chemistry Laboratory, University of Oxford.
    Jones, Jonathan A
    Noppe, Wim
    Dobson, Christopher M
    Independent nucleation and heterogeneous assembly of structure during folding of equine lysozyme1999In: Journal of Molecular Biology, ISSN 0022-2836, E-ISSN 1089-8638, Vol. 289, no 4, p. 1055-1073Article in journal (Refereed)
    Abstract [en]

    The refolding of equine lysozyme from guanidinium chloride has been studied using hydrogen exchange pulse labelling in conjunction with NMR spectroscopy and stopped flow optical methods. The stopped flow optical experiments indicate that extensive hydrophobic collapse occurs rapidly after the initiation of refolding. Pulse labelling experiments monitoring nearly 50 sites within the protein have enabled the subsequent formation of native-like structure to be followed in considerable detail. They reveal that an intermediate having persistent structure within three of the four helices of the alpha-domain of the protein is formed for the whole population of molecules within 4 ms. Subsequent to this event, however, the hydrogen exchange protection kinetics are complex and highly heterogeneous. Analysis of the results by fitting to stretched exponential functions shows that a series of other intermediates is formed as a consequence of the stepwise assembly of independently nucleated local regions of structure. In some molecules the next step in folding involves the stabilisation of the remaining helix in the alpha-domain, whilst in others persistent structure begins to form in the beta-domain. The formation of native-like structure throughout the beta-domain is itself heterogeneous, involving at least three kinetically distinguishable steps. Residues in loop regions throughout the protein attain persistent structure more slowly than regions of secondary structure. There is in addition evidence for locally misfolded regions of structure that reorganise on much longer timescales. The results reveal that the native state of the protein is generated by the heterogeneous assembly of a series of locally cooperative regions of structure. This observation has many features in common with the findings of recent theoretical simulations of protein folding.

  • 66.
    Morozova-Roche, Ludmilla A
    et al.
    Oxford Centre for Molecular Sciences, New Chemistry Laboratory, University of Oxford.
    Zurdo, Jesús
    Spencer, Andrew
    Noppe, Wim
    Receveur, Veronique
    Archer, David B
    Joniau, Marcel
    Dobson, Christopher M
    Amyloid fibril formation and seeding by wild-type human lysozyme and its disease-related mutational variants2000In: Journal of Structural Biology, ISSN 1047-8477, E-ISSN 1095-8657, Vol. 130, no 2-3, p. 339-351Article in journal (Refereed)
    Abstract [en]

    Wild-type human lysozyme and its two stable amyloidogenic variants have been found to form partially folded states at low pH. These states are characterized by extensive disruption of tertiary interactions and partial loss of secondary structure. Incubation of the proteins at pH 2.0 and 37 degrees C (Ile56Thr and Asp67His variants) or 57 degrees C (wild-type) results in the formation of large numbers of fibrils over several days of incubation. Smaller numbers of fibrils could be observed under other conditions, including neutral pH. These fibrils were analyzed by electron microscopy, Congo red birefringence, thioflavine-T binding, and X-ray fiber diffraction, which unequivocally show their amyloid character. These data demonstrate that amyloidogenicity is an intrinsic property of human lysozyme and does not require the presence of specific mutations in its primary structure. The amyloid fibril formation is greatly facilitated, however, by the introduction of "seeds" of preformed fibrils to the solutions of the variant proteins, suggesting that seeding effects could be important in the development of systemic amyloidosis. Fibril formation by wild-type human lysozyme is greatly accelerated by fibrils of the variant proteins and vice versa, showing that seeding is not specific to a given protein. The fact that wild-type lysozyme has not been found in ex vivo deposits from patients suffering from this disease is likely to be related to the much lower population of incompletely folded states for the wild-type protein compared to its amyloidogenic variants under physiological conditions. These results support the concept that the ability to form amyloid is a generic property of proteins, but one that is mitigated against in a normally functioning organism.

  • 67.
    Morozova-Roche, Ludmilla
    et al.
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Berliner, Lawrence J.
    Denver University.
    Permyakov, Eugene A.
    Institute for Biological Instrumentation of the Russian Academy of Sciences.
    Calcium-binding lysozymes2012Book (Other academic)
    Abstract [en]

    In this book, the authors describe an important class of calcium binding lysozymes that are evolutionarily related to the lysozyme superfamily and the lactalbumins. The authors take the reader through a journey from the evolution, then the structure and properties of the calcium binding lysozymes. They discuss new unique protein folding pathways with local cooperative, close related folding modes that exhibit multiple folding pathways which are not properties of the lactalbumins or non calcium binding lysozymes. They comprise one of the most diverse group of examples in protein folding. In addition this protein class, especially equine lysozyme, shows peculiar amyloid assembly properties that are not common with other fibril forming proteins. It is one of the first shown to form ring shaped amyloids and other complexes in vitro. Lastly equine lysozyme forms complex with oleic acid, a unique form ELOA, which contributes to the family of the human and bovine lactalbumin analogs HAMLET and BAMLET.

  • 68.
    Morozova-Roche, Ludmilla
    et al.
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Forsgren, Lars
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Clinical Neuroscience.
    Davis, Jason
    Institutionen för kemi, Oxford universitet, Storbritannien.
    Ny snabbanalys för diagnos av Parkinsons sjukdom2012In: Neurologi i Sverige, ISSN 2000-8538, no 4, p. 74-78Article, review/survey (Other academic)
  • 69.
    Morozova-Roche, Ludmilla
    et al.
    Umeå University, Faculty of Medicine, Medical Biochemistry and Biophsyics.
    Malisauskas, Mantas
    Umeå University, Faculty of Medicine, Medical Biochemistry and Biophsyics.
    A false paradise - mixed blessings in the protein universe: the amyloid as a new challenge in drug development.2007In: Current Medicinal Chemistry, ISSN 0929-8673, Vol. 14, no 11, p. 1221-30Article in journal (Refereed)
  • 70.
    Morozova-Roche, Ludmilla
    et al.
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Zamotin, Vladimir
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Malisauskas, Mantas
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Öhman, Anders
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Chertkova, Rita
    Lavrikova, Marika A
    Kostanyan, Irina A
    Dolgikh, Dmiltry A
    Kirpichnikov, Michail P
    Fibrillation of Carrier Protein Albebetin and Its Biologically Active Constructs. Multiple Oligomeric Intermediates and Pathways2004In: Biochemistry, ISSN 0006-2960, E-ISSN 1520-4995, Biochemistry, Vol. 43, no 30, p. 9610-9619Article in journal (Refereed)
    Abstract [en]

    We showed that the genetically engineered carrier-protein albebetin and its biologically active constructs with interferon-2 octapeptide LKEKKYSP or differentiation factor hexapeptide TGENHR are inherently highly amyloidogenic at physiological pH. The kinetics of fibrillation were monitored by thioflavine-T (ThT) binding and the morphological changes by atomic force microscopy. Fibrillation proceeds via multiple pathways and includes a hierarchy of amyloid structures ranging from oligomers to protofilaments and fibrils. Comparative height and volume microscopic measurements allowed us to identify two distinct types of oligomeric intermediates: pivotal oligomers ca. 1.2 nm in height comprised of 10-12 monomers and on-pathway amyloid-competent oligomers ca. 2 nm in height constituted of 26-30 molecules. The former assemble into chains and rings with "bead-on-string morphology", in which a "bead" corresponds to an individual oligomer. Once formed, the rings and chains remain in solution simultaneously with fibrils. The latter give rise to protofilaments and fibrils, and their formation is concomitant with an increasing level of ThT binding. The amyloid nature of filamentous structures was confirmed by a pronounced ThT and Congo red binding and -sheet-rich far-UV circular dichroism. We suggest that transformation of the pivotal oligomers into the amyloid-prone ones is a limiting stage in amyloid assembly. Peptides, either fused to albebetin or added into solution, and an increased ionic strength promote fibrillation of albebetin (net charge of -12) by counterbalancing critical electrostatic repulsions. This finding demonstrates that the fibrillation of newly designed polypeptide-based products can produce multimeric amyloid species with a potentially "new" functionality, raising questions about their safety.

  • 71. Mossberg, Ann-Kristin
    et al.
    Hun Mok, Kenneth
    Morozova-Roche, Ludmilla A
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Svanborg, Catharina
    Structure and function of human α-lactalbumin made lethal to tumor cells (HAMLET)-type complexes2010In: The FEBS Journal, ISSN 1742-464X, E-ISSN 1742-4658, Vol. 277, no 22, p. 4614-4625Article in journal (Refereed)
    Abstract [en]

    Human α-lactalbumin made lethal to tumor cells (HAMLET) and equine lysozyme with oleic acid (ELOA) are complexes consisting of protein and fatty acid that exhibit cytotoxic activities, drastically differing from the activity of their respective proteinaceous compounds. Since the discovery of HAMLET in the 1990s, a wealth of information has been accumulated, illuminating the structural, functional and therapeutic properties of protein complexes with oleic acid, which is summarized in this review. In vitro, both HAMLET and ELOA are produced by using ion-exchange columns preconditioned with oleic acid. However, the complex of human α-lactalbumin with oleic acid with the antitumor activity of HAMLET was found to be naturally present in the acidic fraction of human milk, where it was discovered by serendipity. Structural studies have shown that α-lactalbumin in HAMLET and lysozyme in ELOA are partially unfolded, 'molten-globule'-like, thereby rendering the complexes dynamic and in conformational exchange. HAMLET exists in the monomeric form, whereas ELOA mostly exists as oligomers and the fatty acid stoichiometry varies, with HAMLET holding an average of approximately five oleic acid molecules, whereas ELOA contains a considerably larger number (11- 48). Potent tumoricidal activity is found in both HAMLET and ELOA, and HAMLET has also shown strong potential as an antitumor drug in different in vivo animal models and clinical studies. The gain of new, beneficial function upon partial protein unfolding and fatty acid binding is a remarkable phenomenon, and may reflect a significant generic route of functional diversification of proteins via varying their conformational states and associated ligands.

  • 72. Musatov, Alexey
    et al.
    Permyakov, Eugine A
    Bagelova, J
    Morozova, Ludmilla
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Snyrov, VL
    Some aspects of fluorescence and microcalorimetric studies of cytochrome C oxidase1990In: Biochemistry international, ISSN 0158-5231, Vol. 21, no 3, p. 563-71Article in journal (Refereed)
    Abstract [en]

    Effects of the solubilizing detergent type, pH and temperature on the structure of cytochrome c oxidase have been studied by the intrinsic fluorescence and scanning microcalorimetry methods. The data obtained allow to conclude that the enzyme solubilization by lauryl maltoside gives a more native preparation in comparison with that obtained by solubilization in Tween 80.

  • 73.
    Nielsen, Søren B
    et al.
    Interdisciplinary Nanoscience Center (iNANO), Department of Molecular Biology, University of Aarhus, Gustav Wieds Vej 10C, DK-8000 Aarhus C, Denmark.
    Wilhelm, Kristina
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Vad, Brian
    Interdisciplinary Nanoscience Center (iNANO), Department of Molecular Biology, University of Aarhus, Gustav Wieds Vej 10C, DK-8000 Aarhus C, Denmark.
    Schleucher, Jürgen
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Morozova-Roche, Ludmilla A
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Otzen, Daniel
    Interdisciplinary Nanoscience Center (iNANO), Department of Molecular Biology, University of Aarhus, Gustav Wieds Vej 10C, DK-8000 Aarhus C, Denmark.
    The interaction of equine lysozyme: oleic acid complexes with lipid membranes suggests a cargo off-loading mechanism2010In: Journal of Molecular Biology, ISSN 0022-2836, E-ISSN 1089-8638, Vol. 398, no 2, p. 351-361Article in journal (Refereed)
    Abstract [en]

    The normal function of equine lysozyme (EL) is the hydrolysis of peptidoglycan residues of bacterial cell walls. EL is closely related to alpha-lactalbumins with respect to sequence and structure and further possesses the calcium binding site of alpha-lactalbumins. Recently, EL multimeric complexes with oleic acids (ELOA) were shown to possess tinctorial and morphological properties, similar to amyloidal aggregates, and to be cytotoxic. ELOA's interactions with phospholipid membranes appears to be central to its biological action, similar to human alpha-lactalbumin made lethal to tumor cells (HAMLET). Here, we describe the interaction of ELOA with phospholipid membranes. Confocal scanning laser microscopy shows that ELOA, but not native EL, accumulates on the surface of giant unilamellar vesicles, without inducing significant membrane permeability. Quartz crystal microbalance with dissipation (QCM-D) data indicated an essentially non-disruptive binding of ELOA to supported lipid bilayers, leading to formation of highly dissipative and "soft" lipid membrane; at higher concentrations of ELOA, the lipid membrane desorbs from the surface probably as bilayer sheets of vesicles. This membrane rearrangement occurred to a similar extent when free oleic acid (OA) was added, but not when free OA was removed from ELOA by prior incubation with BSA, emphasizing the role of OA in this process. NMR data indicated an equilibrium between free and bound OA which shifts towards free OA as ELOA is progressively diluted indicating that OA is relatively loosely bound. Activity measurements together with fluorescence spectroscopy and circular dichroism suggested a conversion of ELOA toward a more native-like state on interaction with lipid membranes, although complete refolding was not observed. Altogether, these results suggest that ELOA may act as an OA carrier and facilitate OA transfer to the membrane. ELOA's properties illustrate that protein folding variants may possess specific functional properties distinct from the native protein. Abbreviations QCM-D, Quartz crystal microbalance with dissipation; CD, Circular dichroism; EL, equine lysozyme; ELOA, EL complex with oleic acid; OA, oleic acid, CSLM, Confocal scanning laser microscopy, Df, dissipation-frequency.

  • 74. Ostrovskaya, RU
    et al.
    Gruden, MA
    Bobkova, NA
    Sewell, RD
    Gudasheva, TA
    Samokhin, AN
    Seredinin, SB
    Noppe, W
    Sherstnev, VV
    Morozova-Roche, Ludmilla
    Umeå University, Faculty of Medicine, Medical Biochemistry and Biophsyics.
    The nootropic and neuroprotective proline-containing dipeptide noopept restores spatial memory and increases immunoreactivity to amyloid in an Alzheimer's disease model.2007In: J Psyckopharmacol, Vol. 21, no 6, p. 611-9Article in journal (Refereed)
  • 75.
    Pansieri, Jonathan
    et al.
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Ostojic, Lucija
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Iashchishyn, Igor
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Magzoub, Mazin
    Wallin, Cecilia
    Warmlander, Sebastian K. T. S.
    Graslund, Astrid
    Ngoc, Mai Nguyen
    Smirnovas, Vytautas
    Svedruzic, Zeljko
    Morozova-Roche, Ludmilla
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Pro-Inflammatory S100A9 Protein Aggregation Promoted by NCAM1 Peptide Constructs2019In: ACS Chemical Biology, ISSN 1554-8929, E-ISSN 1554-8937, Vol. 14, no 7, p. 1410-1417Article in journal (Refereed)
    Abstract [en]

    Amyloid cascade and neuroinflammation are hallmarks of neurodegenerative diseases, and pro-inflammatory S100A9 protein is central to both of them. Here, we have shown that NCAM1 peptide constructs carrying polycationic sequences derived from A beta peptide (KKLVFF) and PrP protein (KKRPKP) significantly promote the S100A9 amyloid self-assembly in a concentration-dependent manner by making transient interactions with individual S100A9 molecules, perturbing its native structure and acting as catalysts. Since the individual molecule misfolding is a rate-limiting step in S100A9 amyloid aggregation, the effects of the NCAM1 construct on the native S100A9 are so critical for its amyloid self-assembly. S100A9 rapid self assembly into large aggregated clumps may prevent its amyloid tissue propagation, and by modulating S100A9 aggregation as a part of the amyloid cascade, the whole process may be effectively tuned.

  • 76.
    Permyakov, E A
    et al.
    Institute of Biological Physics, Pushchino, Russia.
    Kalinichenko, L P
    Morozova, L A
    Institute of Biological Physics, Pushchino, Russia.
    Yarmolenko, V V
    Burstein, E A
    alpha-Lactalbumin binds magnesium ions: study by means of intrinsic fluorescence technique.1981In: Biochemical and Biophysical Research Communications - BBRC, ISSN 0006-291X, E-ISSN 1090-2104, Vol. 102, no 1, p. 1-7Article in journal (Refereed)
  • 77. Permyakov, E A
    et al.
    Morozova, L A
    Institute of Biological Physics, Pushchino, Russia.
    Burstein, E A
    Cation binding effects on the pH, thermal and urea denaturation transitions in alpha-lactalbumin.1985In: Biophysical Chemistry, ISSN 0301-4622, E-ISSN 1873-4200, Vol. 21, no 1, p. 21-31Article in journal (Refereed)
    Abstract [en]

    The binding of monovalent (Na+, K+) and divalent (Ca2+, Mg2+) cations to bovine alpha-lactalbumin at 20 and 37 degrees C has been studied by means of intrinsic protein fluorescence. The values of apparent binding constants for these ions obtained at 37 degrees C are about one order of magnitude lower than those measured at 20 degrees C. Urea and alkali (pH greater than 10) induce unfolding transitions which involve stable partially unfolded intermediates for all metal ion-bound forms of alpha-lactalbumin. Heating induces similar partially unfolded states. Nevertheless, the partially unfolded states induced by heating, urea, alkaline or acidic treatments are somewhat different in their tryptophan residue environment properties. The results have been interpreted in terms of a simple scheme of equilibria between metal-free and metal-bound forms in their native, partially unfolded and unfolded states. The scheme provides an approach to the quantitative interpretation of any transition equilibrium shift induced by a low molecular mass species able to be bound by a protein.

  • 78.
    Permyakov, E A
    et al.
    Institute of Biological Physics, Pushchino, Russia.
    Morozova, L A
    Institute of Biological Physics, Pushchino, Russia.
    Kalinichenko, L P
    Derezhkov, V Yu
    Interaction of alpha-lactalbumin with Cu2+.1988In: Biophysical Chemistry, ISSN 0301-4622, E-ISSN 1873-4200, Vol. 32, no 1, p. 37-42Article in journal (Refereed)
    Abstract [en]

    It has been shown by intrinsic fluorescence spectroscopy that alpha-lactalbumin has several Cu2+ -binding sites per molecule. The Ca2+ -loaded protein binds two or more Cu2+ per molecule with an association constant of about 3 X 10(3) M-1. Apo-alpha-lactalbumin binds one Cu2+ per molecule with association constant 8 X 10(4) M-1 and from two to three Cu2+ with an association constant of about 4 X 10(3) M-1. The results obtained from spectrofluorometric pH titration of alpha-lactalbumin in the acidic pH region show the possible involvement of histidine residues in the coordination of Cu2+. The binding of Cu2+ to alpha-lactalbumin lowers significantly its thermostability and stability towards urea denaturation. The stability of Cu2+, Ca2+-alpha-lactalbumin against thermal and urea denaturation is similar to that of the apo protein. The thermal transition in Cu2+, Ca2+-alpha-lactalbumin occurs within the region of physiological temperatures which may suggest the existence of some thermal regulation of its functioning in vivo.

  • 79. Permyakov, E A
    et al.
    Yarmolenko, V V
    Kalinichenko, L P
    Morozova, L A
    Institute of Biological Physics, Pushchino, Russia.
    Burstein, E A
    Calcium binding to alpha-lactalbumin: structural rearrangement and association constant evaluation by means of intrinsic protein fluorescence changes.1981In: Biochemical and Biophysical Research Communications - BBRC, ISSN 0006-291X, E-ISSN 1090-2104, Vol. 100, no 1, p. 191-7Article in journal (Refereed)
  • 80.
    Permyakov, Eugene A.
    et al.
    (Institute for Biological Instrumentation of the Russian Academy of Sciences, Pushchino, Moscow region, Russia.
    Morozova-Roche, Ludmilla
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Berliner, Lawrence J.
    Denver University, Denver, Colorado.
    Calcium Binding Lysozymes2012Book (Other academic)
  • 81. Permyakov, Eugene A
    et al.
    Permyakov, Serge E
    Deikus, Gintaras Y
    Morozova-Roche, Ludmila A
    Umeå University, Faculty of Science and Technology, Department of Chemistry. Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Grishchenko, Valery M
    Kalinichenko, Lina P
    Uversky, Vladimir N
    Ultraviolet illumination-induced reduction of alpha-lactalbumin disulfide bridges2003In: Proteins: Structure, Function, and Bioinformatics, Vol. 51, no 4, p. 498-503Article in journal (Refereed)
    Abstract [en]

    Prolonged exposure of Ca2+-loaded or Ca2+-depleted human -lactalbumin to ultraviolet light (270-290 nm, 1 mW/cm2, for 2 to 4 h) results in a 10-nm red shift of its tryptophan fluorescence spectrum. Gel chromatography of the UV-illuminated samples reveals two non-native protein forms: (1) a component with a red-shifted tryptophan fluorescence spectrum; and (2) a component with kynurenine-like fluorescent properties. The first component has from 0.6 to 0.9 free DTNB-reactive SH groups per protein molecule, which are absent in the native protein and is characterized by slightly lowered Ca2+-affinity (2 × 108 M-1 versus 8 × 108 M-1 for the native protein) and absence of observable thermal transition. The second component corresponds to the protein with photochemically modified tryptophan residues. It is assumed that the UV excitation of tryptophan residue(s) in -lactalbumin is followed by a transfer of electrons to the SS bonds, resulting in their reduction. Mass spectrometry data obtained for trypsin-fragmented UV-illuminated -lactalbumin with acrylodan-modified free thiol groups reveal the reduction of the 61-77 and 73-91 disulfide bridges. The effect observed has to be taken into account in any UV-region spectral studies of -lactalbumin. Proteins 2003;51:498-503.

  • 82. Permyakov, Sergei E
    et al.
    Khokhlova, Tatyana I
    Nazipova, Aliya A
    Zhadan, Andrey P
    Morozova-Roche, Ludmilla
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Permyakov, Eugene A
    Calcium-binding and temperature induced transitions in equine lysozyme: new insights from the pCa-temperature "phase diagrams".2006In: Proteins: Structure, Function, and Bioinformatics, ISSN 0887-3585, E-ISSN 1097-0134, Vol. 65, no 4, p. 984-98Article in journal (Refereed)
  • 83. Perálvarez-Marín, Alex
    et al.
    Mateos, Laura
    Zhang, Ce
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Singh, Shalini
    Cedazo-Mínguez, Angel
    Visa, Neus
    Morozova-Roche, Ludmilla
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Gräslund, Astrid
    Barth, Andreas
    Influence of residue 22 on the folding, aggregation profile, and toxicity of the Alzheimer's amyloid β peptide2009In: Biophysical Journal, ISSN 0006-3495, E-ISSN 1542-0086, Vol. 97, no 1, p. 277-285Article in journal (Refereed)
    Abstract [en]

    Several biophysical techniques have been used to determine differences in the aggregation profile (i.e., the secondary structure, aggregation propensity, dynamics, and morphology of amyloid structures) and the effects on cell viability of three variants of the amyloid beta peptide involved in Alzheimer's disease. We focused our study on the Glu22 residue, comparing the effects of freshly prepared samples and samples aged for at least 20 days. In the aged samples, a high propensity for aggregation and beta-sheet secondary structure appears when residue 22 is capable of establishing polar (Glu22 in wild-type) or hydrophobic (Val22 in E22V) interactions. The Arctic variant (E22G) presents a mixture of mostly disordered and alpha-helix structures (with low beta-sheet contribution). Analysis of transmission electron micrographs and atomic force microscopy images of the peptide variants after aging showed significant quantitative and qualitative differences in the morphology of the formed aggregates. The effect on human neuroblastoma cells of these Abeta(12-28) variants does not correlate with the amount of beta-sheet of the aggregates. In samples allowed to age, the native sequence was found to have an insignificant effect on cell viability, whereas the Arctic variant (E22G), the E22V variant, and the slightly-aggregating control (F19G-F20G) had more prominent effects.

  • 84.
    Röhrig, Ursula
    et al.
    Max-Planck Institute, Department of Cell Biology, Martinsried, Germany.
    Gerisch, Günther
    Morozova, Ludmilla
    Max-Planck Institute, Department of Cell Biology, Martinsried, Germany.
    Schleicher, Michael
    Wegner, Albrecht
    Coactosin interferes with the capping of actin filaments1995In: FEBS Letters, ISSN 0014-5793, E-ISSN 1873-3468, Vol. 374, no 2, p. 284-286Article in journal (Refereed)
    Abstract [en]

    Coactosin, a 16 kDa protein associated with the actin cytoskeleton from Dictyostelium discoideum, was purified by an improved method, in which other components of the cytoskeleton were removed. The highly purified coactosin had no effect on the time course of actin polymerization, but when added to actin in presence of capping proteins, coactosin counteracted the capping activity of these proteins. The capping proteins cap32/34 and severin domain 1 retarded actin polymerization, on addition of coactosin to samples containing one of these capping proteins the time course of actin polymerization became close to controls without capping proteins.

  • 85. Van Dael, Herman
    et al.
    Haezebrouck, Petra
    Morozova, Ludmilla
    Max Planck Institute fur Biochemie, Martinsried, Germany.
    Arico-Muendel, Christopher
    Dobson, Christopher M
    Partially folded states of equine lysozyme. Structural characterization and significance for protein folding.1993In: Biochemistry, ISSN 0006-2960, E-ISSN 1520-4995, Vol. 32, no 44, p. 11886-11894Article in journal (Refereed)
    Abstract [en]

    Despite their homologous structure, c-type lysozymes and alpha-lactalbumins have been found to differ profoundly in their unfolding behavior, in that the alpha-lactalbumins readily enter a partially unfolded collapsed state (the "molten globule"), whereas lysozymes unfold cooperatively to a highly unfolded state. The calcium-binding property of lysozyme from equine milk provides an evolutionary link between the two families of proteins. We demonstrate here that equine lysozyme undergoes a two-stage unfolding transition upon heating or in the presence of guanidine hydrochloride that is highly dependent on the state of calcium binding. Differential scanning calorimetry shows the two transitions to be particularly well resolved in the calcium-free protein, where the first transition occurs with a midpoint at 44 degrees C at pH 4.5 or in 0.8 M GdnHCl at pH 7.5, 25 degrees C, and the second occurs near 70 degrees C at pH 4.5 or in 3.7 M GdnHCl at pH 7.5, 25 degrees C. In the presence of calcium, the first transition takes place with a midpoint of 55 degrees C or in excess of 2.5 M GdnHCl, but the parameters for the second transition remain unchanged. Fluorescence emission and UV difference absorption spectroscopy suggest that the first transition generates an intermediate state in which sequestration of some aromatic side chains from solvent has occurred whereas the second represents denaturation to a highly unfolded state. CD and 1H NMR results indicate that the intermediate state possesses extensive secondary and tertiary structure, although the latter is substantially disordered.(ABSTRACT TRUNCATED AT 250 WORDS)

  • 86. Vetri, Valeria
    et al.
    Leone, Maurizio
    Morozova-Roche, Ludmilla A.
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Vestergaard, Bente
    Fodera, Vito
    Unlocked Concanavalin A Forms Amyloid-like Fibrils from Coagulation of Long-lived "Crinkled'' Intermediates2013In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 8, no 7, p. e68912-Article in journal (Refereed)
    Abstract [en]

    Understanding the early events during amyloid aggregation processes is crucial to single out the involved molecular mechanisms and for designing ad hoc strategies to prevent and reverse amyloidogenic disorders. Here, we show that, in conditions in which the protein is positively charged and its conformational flexibility is enhanced, Concanavalin A leads to fibril formation via a non-conventional aggregation pathway. Using a combination of light scattering, circular dichroism, small angle X-ray scattering, intrinsic (Tryptophan) and extrinsic (ANS) fluorescence and confocal and 2-photon fluorescence microscopy we characterize the aggregation process as a function of the temperature. We highlight a multi-step pathway with the formation of an on-pathway long-lived intermediate and a subsequent coagulation of such "crinkled'' precursors into amyloid-like fibrils. The process results in a temperature-dependent aggregation-coagulation pathway, with the late phase of coagulation determined by the interplay between hydrophobic and electrostatic forces. Our data provide evidence for the complex aggregation pathway for a protein with a highly flexible native conformation. We demonstrate the possibility to generate a long-lived intermediate whose proportion and occurrence are easily tunable by experimental parameters (i.e. temperature). As a consequence, in the case of aggregation processes developing through well-defined energy barriers, our results can open the way to new strategies to induce more stable in vitro on-pathway intermediate species through a minute change in the initial conformational flexibility of the protein. This will allow isolating and experimentally studying such transient species, often indicated as relevant in neurodegenerative diseases, both in terms of structural and cytotoxic properties.

  • 87.
    Vogl, Thomas
    et al.
    Institute of Immunology, University of Muenster, Germany.
    Gharibyan, Anna
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Morozova-Roche, Ludmilla
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Pro-Inflammatory S100A8 and S100A9 Proteins: Self-Assembly into Multifunctional Native and Amyloid Complexes2012In: International Journal of Molecular Sciences, ISSN 1422-0067, E-ISSN 1422-0067, Vol. 13, no 3, p. 2893-2917Article in journal (Refereed)
    Abstract [en]

    S100A8 and S100A9 are EF-hand Ca2+ binding proteins belonging to the S100 family. They are abundant in cytosol of phagocytes and play critical roles in numerous cellular processes such as motility and danger signaling by interacting and modulating the activity of target proteins. S100A8 and S100A9 expression levels increased in many types of cancer, neurodegenerative disorders, inflammatory and autoimmune diseases and they are implicated in the numerous disease pathologies. The Ca2+ and Zn2+-binding properties of S100A8/A9 have a pivotal influence on their conformation and oligomerization state, including self-assembly into homo- and heterodimers, tetramers and larger oligomers. Here we review how the unique chemical and conformational properties of individual proteins and their structural plasticity at the quaternary level account for S100A8/A9 functional diversity. Additional functional diversification occurs via non-covalent assembly into oligomeric and fibrillar amyloid complexes discovered in the aging prostate and reproduced in vitro. This process is also regulated by Ca2+ and Zn2+-binding and effectively competes with the formation of the native complexes. High intrinsic amyloid-forming capacity of S100A8/A9 proteins may lead to their amyloid depositions in numerous ailments characterized by their elevated expression patterns and have additional pathological significance requiring further thorough investigation.

  • 88.
    Vukojevic, Vladana
    et al.
    Department of Clinical Neuroscience, Karolinska Institutet, 17176 Stockholm, Sweden.
    Bowen, Alice M
    Department of Chemistry, University of Oxford, Physical and Theoretical Chemistry Laboratory, Oxford OX1 3QZ, U.K..
    Wilhelm, Kristina
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Ming, Yu
    Department of Clinical Neuroscience, Karolinska Institutet, 17176 Stockholm, Sweden.
    Schleucher, Jürgen
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Hore, PJ
    Department of Chemistry, University of Oxford, Physical and Theoretical Chemistry Laboratory, Oxford OX1 3QZ, U.K..
    Terenius, Lars
    Department of Clinical Neuroscience, Karolinska Institutet, 17176 Stockholm, Sweden.
    Morozova-Roche, Ludmilla A
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Ce, Zhang
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Lipoprotein complex of equine lysozyme with oleic acid (ELOA) interactions with the plasma membrane of live cells2010In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 26, no 18, p. 14782-14787Article in journal (Refereed)
    Abstract [en]

    Recent evidence supports the idea that early aggregates, protein, and lipoprotein oligomers but not large aggregates like fibrils that are formed at late stages of the aggregation process are responsible for cytotoxicity. Oligomers can interact with the cellular plasma membrane affecting its structure and/or dynamics or may be taken up by the cells. In either case, disparate cascades of molecular interactions are activated in the attempt to counteract the disturbance induced by the oligomers. If unsuccessful, cell death follows. Here, we study the molecular and cellular mechanisms underlying PC12 cell death caused by ELOA oligomers. ELOA, a lipoprotein complex formed by equine lysozyme (EL) and oleic acid (OA), induces cell death in all tested cell lines, but the actual mechanism of its action is not known. We have used methods with single-molecule sensitivity, fluorescence correlation spectroscopy (FCS), fluorescence cross-correlation spectroscopy (FCCS), and confocal laser scanning microscopy (CLSM) imaging by avalanche photodiodes (APD), so-called APD imaging, to study ELOA interactions with the plasma membrane in live PC12 cells. We detected ELOA accumulation in the cell surroundings, observed ELOA interactions with the plasma membrane, and local changes in plasma membrane lipid dynamics in the vicinity of ELOA complexes. These interactions resulted in plasma membrane rupture, followed by rapid influx and distribution of ELOA inside the already dead cell. In order to probe the ELOA−plasma membrane interaction sites at the molecular and atomic levels, the ELOA complexes were further studied by photochemically induced dynamic nuclear polarization (photo-CIDNP) spectroscopy, nuclear magnetic resonance (NMR) and atomic force microscopy (AFM). We observed a novel mechanism of oligomer toxicity−cell death induced by continuous disturbance of the plasma membrane, eventually causing permanent plasma membrane damage and identified the sites in ELOA that are potentially involved in the interactions with the plasma membrane.

  • 89.
    Vukojevic, Vladana
    et al.
    Department of Clinical Neuroscience, Karolinska Institute.
    Morozova-Roche, Ludmilla
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Structural origin of ELOA toxicity: implication for HAMLET-type protein complexes with oleic acid2012In: Lipoproteins - Role in Health and Diseases / [ed] Sasa Frank and Gerhard Kostner, InTech, 2012, p. 663-674Chapter in book (Other academic)
  • 90.
    Wang, Chao
    et al.
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Iashchishyn, Igor
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Kara, John
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Fodera, Vito
    Vetri, Valeria
    Sancataldo, Giuseppe
    Marklund, Niklas
    Morozova-Roche, Ludmilla
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Proinflammatory and amyloidogenic S100A9 induced by traumatic brain injury in mouse model2019In: Neuroscience Letters, ISSN 0304-3940, E-ISSN 1872-7972, Vol. 699, p. 199-205Article in journal (Refereed)
    Abstract [en]

    Traumatic brain injury (TBI) represents a significant risk factor for development of neurodegenerative diseases such as Alzheimer's and Parkinson's. The S100A9-driven amyloid-neuroinflammatory cascade occurring during primary and secondary TBI events can serve as a mechanistic link between TBI and Alzheimer's as demonstrated recently in the human brain tissues. Here by using immunohistochemistry in the controlled cortical impact TBI mouse model we have found pro-inflammatory S100A9 in the brain tissues of all mice on the first and third post- TBI days, while 70% of mice did not show any S100A9 presence on seventh post-TBI day similar to controls. This indicates that defensive mechanisms effectively cleared S100A9 in these mouse brain tissues during post-TBI recovery. By using sequential immunohistochemistry we have shown that S100A9 was produced by both neuronal and microglial cells. However, A beta peptide deposits characteristic for Alzheimer's disease were not detected in any post-TBI animals. On the first and third post-TBI days S100A9 was found to aggregate intracellularly into amyloid oligomers, similar to what was previously observed in human TBI tissues. Complementary, by using Rayleigh scatting, intrinsic fluorescence and atomic force microscopy we demonstrated that in vitro S100A9 self- assembles into amyloid oligomers within minutes. Its amyloid aggregation is highly dependent on changes of environmental conditions such as variation of calcium levels, pH, temperature and reduction/oxidation, which might be relevant to perturbation of cellular and tissues homeostasis under TBI. Present results demonstrate that S100A9 induction mechanisms in TBI are similar in mice and humans, emphasizing that S100A9 is an important marker of brain injury and therefore can be a potential therapeutic target.

  • 91.
    Wang, Chao
    et al.
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Iashchishyn, Igor
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Nyström, Sofie
    Klementieva, Oxana
    Kara, John
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Bengtsson, Sara
    Umeå University, Faculty of Medicine, Department of Clinical Sciences.
    Foderà, Vito
    Vetri, Valeria
    Sancataldo, Giuseppe
    Horvath, Istvan
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Moskalenko, Roman
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics. Department of Pathology, Sumy State University, Sumy, Ukraine.
    Rofougaran, Reza
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Bäckström, Torbjörn
    Umeå University, Faculty of Medicine, Department of Clinical Sciences.
    Wang, Mingde
    Umeå University, Faculty of Medicine, Department of Clinical Sciences.
    Gouras, Gunnar
    Marklund, Niklas
    Shankar, S.K.
    Morozova-Roche, Ludmilla
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    S100A9-driven amyloid-neuroinflammatory cascade in traumatic brain injury as a risk factor for Alzheimer’s diseaseManuscript (preprint) (Other academic)
  • 92.
    Wang, Chao
    et al.
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Iashchishyn, Igor
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics. Department of General Chemistry, Sumy State University, Sumy, 40000, Ukraine.
    Pansieri, Jonathan
    Nyström, Sofie
    Klementieva, Oxana
    Kara, John
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Horvath, Istvan
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Moskalenko, Roman
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics. Department of Pathology, Sumy State University, Sumy, 40000, Ukraine.
    Rofougaran, Reza
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Gouras, Gunnar
    Kovacs, Gabor G.
    Shankar, S. K.
    Morozova-Roche, Ludmilla
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    S100A9-Driven Amyloid-Neuroinflammatory Cascade in Traumatic Brain Injury as a Precursor State for Alzheimer's Disease2018In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 8, article id 12836Article in journal (Refereed)
    Abstract [en]

    Pro-inflammatory and amyloidogenic S100A9 protein is an important contributor to Alzheimer's disease (AD) pathology. Traumatic brain injury (TBI) is viewed as a precursor state for AD. Here we have shown that S100A9-driven amyloid-neuroinflammatory cascade was initiated in TBI and may serve as a mechanistic link between TBI and AD. By analyzing the TBI and AD human brain tissues, we demonstrated that in post-TBI tissues S100A9, produced by neurons and microglia, becomes drastically abundant compared to A beta and contributes to both precursor-plaque formation and intracellular amyloid oligomerization. Conditions implicated in TBI, such as elevated S100A9 concentration, acidification and fever, provide strong positive feedback for S100A9 nucleation-dependent amyloid formation and delay in its proteinase clearance. Consequently, both intracellular and extracellular S100A9 oligomerization correlated with TBI secondary neuronal loss. Common morphology of TBI and AD plaques indicated their similar initiation around multiple aggregation centers. Importantly, in AD and TBI we found S100A9 plaques without A beta. S100A9 and A beta plaque pathology was significantly advanced in AD cases with TBI history at earlier age, signifying TBI as a risk factor. These new findings highlight the detrimental consequences of prolonged post-TBI neuroinflammation, which can sustain S100A9-driven amyloid-neurodegenerative cascade as a specific mechanism leading to AD development.

  • 93.
    Wang, Chao
    et al.
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Klechikov, Alexey G.
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Gharibyan, Anna L.
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Wärmländer, Sebastian K. T. S.
    Jarvet, Jüri
    Zhao, Lina
    Jia, Xueen
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Shankar, S. K.
    Olofsson, Anders
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Brännström, Thomas
    Umeå University, Faculty of Medicine, Department of Medical Biosciences, Pathology.
    Mu, Yuguang
    Gräslund, Astrid
    Morozova-Roche, Ludmilla A.
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    The role of pro-inflammatory S100A9 in Alzheimer's disease amyloid-neuroinflammatory cascade2014In: Acta Neuropathologica, ISSN 0001-6322, E-ISSN 1432-0533, Vol. 127, no 4, p. 507-522Article in journal (Refereed)
    Abstract [en]

    Pro-inflammatory S100A9 protein is increasingly recognized as an important contributor to inflammation-related neurodegeneration. Here, we provide insights into S100A9 specific mechanisms of action in Alzheimer's disease (AD). Due to its inherent amyloidogenicity S100A9 contributes to amyloid plaque formation together with A beta. In traumatic brain injury (TBI) S100A9 itself rapidly forms amyloid plaques, which were reactive with oligomer-specific antibodies, but not with A beta and amyloid fibrillar antibodies. They may serve as precursor-plaques for AD, implicating TBI as an AD risk factor. S100A9 was observed in some hippocampal and cortical neurons in TBI, AD and non-demented aging. In vitro S100A9 forms neurotoxic linear and annular amyloids resembling A beta protofilaments. S100A9 amyloid cytotoxicity and native S100A9 pro-inflammatory signaling can be mitigated by its co-aggregation with A beta, which results in a variety of micron-scale amyloid complexes. NMR and molecular docking demonstrated transient interactions between native S100A9 and A beta. Thus, abundantly present in AD brain pro-inflammatory S100A9, possessing also intrinsic amyloidogenic properties and ability to modulate A beta aggregation, can serve as a link between the AD amyloid and neuroinflammatory cascades and as a prospective therapeutic target.

  • 94.
    Wilhelm, Kristina
    et al.
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Darinskas, A
    Noppe, W
    Duchardt, E
    Mok, KH
    Vukojevic, V
    Schleucher, Jürgen
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Morozova-Roche, Ludmilla
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Protein oligomerization induced by oleic acid at the solidliquid interface: equine lysozyme cytotoxic complexes2009In: The FEBS Journal, ISSN 1742-464X, E-ISSN 1742-4658, Vol. 276, no 15, p. 3975-3989Article in journal (Refereed)
    Abstract [en]

    Protein oligomeric complexes have emerged as a major target of current research because of their key role in aggregation processes in living systems and in vitro. Hydrophobic and charged surfaces may favour the self-assembly process by recruiting proteins and modifying their interactions. We found that equine lysozyme assembles into multimeric complexes with oleic acid (ELOA) at the solid–liquid interface within an ion-exchange chromatography column preconditioned with oleic acid. The properties of ELOA were characterized using NMR, spectroscopic methods and atomic force microscopy, and showed similarity with both amyloid oligomers and the complexes with oleic acid and its structural homologous protein α-lactalbumin, known as humanα-lactalbumin made lethal for tumour cells (HAMLET). As determined by NMR diffusion measurements, ELOA may consist of 4–30 lysozyme molecules. Each lysozyme molecule is able to bind 11–48 oleic acids in various preparations. Equine lysozyme acquired a partially unfolded conformation in ELOA, as evident from its ability to bind hydrophobic dye 8-anilinonaphthalene-1-sulfonate. CD and NMR spectra. Similar to amyloid oligomers, ELOA also interacts with thioflavin-T dye, shows a spherical morphology, assembles into ring-shaped structures, as monitored by atomic force microscopy, and exerts a toxic effect in cells. Studies of well-populated ELOA shed light on the nature of the amyloid oligomers and HAMLET complexes, suggesting that they constitute one large family of cytotoxic proteinaceous species. The hydrophobic surfaces can be used profitably to produce complexes with very distinct properties compared to their precursor proteins.

  • 95.
    Wilhelm, Kristina R
    et al.
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Yanamandra, Kiran
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Gruden, M A
    P.K. Anokhin Institute of Normal Physiology, Russian Academy of Medical Sciences, Moscow, Russia.
    Zamotin, V
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Malisauskas, M
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Casaite, V
    Department of Molecular Microbiology and Biotechnology, Institute of Biochemistry, Vilnius, Lithuania.
    Darinskas, A
    Institute of Immunology, Vilnius University, Vilnius, Lithuania.
    Forsgren, Lars
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Neurology.
    Morozova-Roche, Ludmilla A
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Immune reactivity towards insulin, its amyloid and protein S100B in blood sera of Parkinson's disease patients2007In: European Journal of Neurology, ISSN 1351-5101, E-ISSN 1468-1331, Vol. 14, no 3, p. 327-334Article in journal (Refereed)
    Abstract [en]

    Peripheral immune responses can be sensitive indicators of disease pathology. We evaluated the autoimmune reactions to endocrine (insulin) and astrocytical (S100B) biomarkers in the blood sera of 26 Parkinson's disease (PD) patients compared with controls by using ELISA. We found a statistically significant increase of the autoimmune responses to both antigens in PD patients compared with controls with a mean increase of 70% and 50% in the autoimmune reactions towards insulin and S100B, respectively. Heterogeneity of the immune responses observed in patients may reflect the modulating effect of multiple variables associated with neurodegeneration and also changes in the basic mechanisms of individual autoimmune reactivity. We did not detect any pronounced immune reactions towards insulin amyloid fibrils and oligomers in PD patients, indicating that an amyloid-specific conformational epitope is not involved in immune recognition of this amyloid type, while sequential epitope of native insulin is hidden within the amyloid structures. Immune reactions towards S100B and insulin may reflect the neurodegenerative brain damaging processes and impaired insulin homeostasis occurring in PD.

  • 96. Williamson, Philip T. F.
    et al.
    Horrocks, Jack
    Maheswaran, Luckshi
    Concistre, Maria
    Morozova-Roche, Ludmilla
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Unravelling the Role of S100A9 in the Development of Neurodegenerative Disease2019In: Biophysical Journal, ISSN 0006-3495, E-ISSN 1542-0086, Vol. 116, no 3, p. 338A-338AArticle in journal (Other academic)
  • 97. Xu, Weixin
    et al.
    Zhang, Ce
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Derreumaux, Philippe
    Graslund, Astrid
    Morozova-Roche, Ludmilla
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Mu, Yuguang
    Intrinsic determinants of A beta(12-24) pH-dependent self-assembly revealed by combined computational and experimental studies2011In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 6, no 9, p. e24329-Article in journal (Refereed)
    Abstract [en]

    The propensity of amyloid-beta (A beta) peptide to self-assemble into highly ordered amyloid structures lies at the core of their accumulation in the brain during Alzheimer's disease. By using all-atom explicit solvent replica exchange molecular dynamics simulations, we elucidated at the atomic level the intrinsic determinants of the pH-dependent dimerization of the central hydrophobic segment A beta(12-24) and related these with the propensity to form amyloid fibrils measured by experimental tools such as atomic force microscopy and fluorescence. The process of A beta(12-24) dimerization was evaluated in terms of free energy landscape, side-chain two-dimensional contact probability maps, beta-sheet registries, potential mean force as a function of inter-chain distances, secondary structure development and radial solvation distributions. We showed that dimerization is a key event in A beta(12-24) amyloid formation; it is highly prompted in the order of pH 5.0 > 2.9 > > 8.4 and determines further amyloid growth. The dimerization is governed by a dynamic interplay of hydrophobic, electrostatic and solvation interactions permitting some variability of beta-sheets at each pH. These results provide atomistic insight into the complex process of molecular recognition detrimental for amyloid growth and pave the way for better understanding of the molecular basis of amyloid diseases.

  • 98.
    Xu, Weixin
    et al.
    East China Normal University, Shanghai, China.
    Zhang, Ce
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Morozova-Roche, Ludmilla
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Zhang, John Z H
    East China Normal University, Shanghai, China.
    Mu, Yuguang
    School of Biological Sciences, Nanyang Technological University, Singapore.
    pH-Dependent Conformational Ensemble and Polymorphism of Amyloid-beta Core Fragment2013In: Journal of Physical Chemistry B, ISSN 1520-6106, E-ISSN 1520-5207, Vol. 117, no 28, p. 8392-9Article in journal (Refereed)
    Abstract [en]

    Characterization of amyloid oligomeric species is important due to its possible responsibility for the toxicity of amyloid proteins, whereas it is difficult to detect by current spectroscopic techniques. The pH-dependent tetramerization and fibrillation of the central hydrophobic segment of Alzheimer amyloid β-peptide (Aβ(12-24)) were respectively explored by all-atom replica exchange molecular dynamics simulations and by fluorescence and atomic force microscopy measurements. Our combined study shows that more β-sheet structures in the early event of tetramerization is linked directly to the high propensity to form amyloid fibrils in the consequent fibrillation. Both tetramerization and fibrillation are strongly regulated by pH. At pH 5.0, Aβ(12-24) has two opposite terminal charges. The electrostatic attraction between the side-chains of His13/His14 and Glu22/Asp23 thus acts as a "pattern keeper", resulting in high propensity of amyloid formation. These results suggest that pH effects most likely by affecti