Umeå University's logo

umu.sePublications
Change search
CiteExportLink to record
Permanent link

Direct 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
The N-terminal domain of TWINKLE contributes to single-stranded DNA binding and DNA helicase activities.
Umeå University, Faculty of Medicine, Medical Biochemistry and Biophsyics.
Show others and affiliations
2008 (English)In: Nucleic Acids Research, ISSN 0305-1048, E-ISSN 1362-4962, Vol. 36, no 2, p. 393-403Article in journal (Refereed) Published
Place, publisher, year, edition, pages
2008. Vol. 36, no 2, p. 393-403
Identifiers
URN: urn:nbn:se:umu:diva-6621DOI: 10.1093/nar/gkm1025PubMedID: 18039713Scopus ID: 2-s2.0-39149116732OAI: oai:DiVA.org:umu-6621DiVA, id: diva2:146291
Available from: 2008-03-07 Created: 2008-03-07 Last updated: 2023-03-24Bibliographically approved
In thesis
1. DNA precursor biosynthesis-allosteric regulation and medical applications
Open this publication in new window or tab >>DNA precursor biosynthesis-allosteric regulation and medical applications
2008 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Ribonucleotide reductase (RNR) is a key enzyme for de novo dNTP biosynthesis. We have studied nucleotide-dependent oligomerization of the allosterically regulated mammalian RNR using a mass spectrometry–related technique called Gas-phase Electrophoretic Mobility Macromolecule Analysis (GEMMA). Our results showed that dATP and ATP induce the formation of an α6β2 protein complex. This complex can either be active or inactive depending on whether ATP or dATP is bound.

In order to understand whether formation of the large complexes is a general feature in the class Ia RNRs, we compared the mammalian RNR to the E. coli enzyme. The E. coli protein is regarded a prototype for all class Ia RNRs. We found that the E. coli RNR cycles between an active α2β2 form (in the presence of ATP, dTTP or dGTP) and an inactive α4β4 form in the presence of dATP or a combination of ATP with dTTP/dGTP. The E. coli R1 mutant (H59A) which needs higher dATP concentrations to be inhibited than the wild-type enzyme had decreased ability to form these complexes. It remains to be discovered how the regulation functions in the mammalian enzyme where both the active and inactive forms are α6β2 complexes.

An alternative way to produce dNTPs is via salvage biosynthesis where deoxyribonucleosides are taken up from outside the cell and phosphorylated by deoxyribonucleoside kinases. We have found that the pathogen Trypanosoma brucei, which causes African sleeping sickness, has a very efficient salvage of adenosine, deoxyadenosine and adenosine analogs such as adenine arabinoside (Ara-A). One of the conclusions made was that this nucleoside analog is phosphorylated by the T. brucei adenosine kinase and kills the parasite by causing nucleotide pool imbalances and by incorporation into nucleic acids. Ara-A-based therapies can hopefully be developed into new medicines against African sleeping sickness.

Generally, the dNTPs produced from the de novo and salvage pathways can be imported into mitochondria and participate in mtDNA replication. The minimal mtDNA replisome contains DNA polymerase γA, DNA polymerase γB, helicase (TWINKLE) and the mitochondrial single-stranded DNA-binding protein (mtSSB). Here, it was demonstrated that the primase-related domain (N-terminal region) of the TWINKLE protein lacked primase activity and instead contributes to single-stranded DNA binding and DNA helicase activities. This region is not absolutely required for mitochondrial DNA replisome function but is needed for the formation of long DNA products.

Place, publisher, year, edition, pages
Umeå: Medicinsk kemi och biofysik, 2008. p. 29
Series
Umeå University medical dissertations, ISSN 0346-6612 ; 1175
Keywords
Biochemistry, DNA biosynthesis, ribonucleotide reductase, allosteric regulation, Trypanosoma brucei, adenosine kinase, nucleoside analogs, mitochondrial DNA, TWINKLE, Biokemi
National Category
Medical Biotechnology (with a focus on Cell Biology (including Stem Cell Biology), Molecular Biology, Microbiology, Biochemistry or Biopharmacy) Biochemistry and Molecular Biology
Research subject
Medical Biochemistry
Identifiers
urn:nbn:se:umu:diva-1678 (URN)978-91-7264-558-5 (ISBN)
Public defence
2008-06-13, KB3A9, KBC Huset, Umeå University, SE-90187, Umeå, 13:00 (English)
Opponent
Supervisors
Available from: 2008-05-27 Created: 2008-05-27 Last updated: 2014-01-22Bibliographically approved

Open Access in DiVA

No full text in DiVA

Other links

Publisher's full textPubMedScopushttp://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Retrieve&list_uids=18039713&dopt=Citation

Authority records

Hofer, Anders

Search in DiVA

By author/editor
Hofer, Anders
By organisation
Medical Biochemistry and Biophsyics
In the same journal
Nucleic Acids Research

Search outside of DiVA

GoogleGoogle Scholar

doi
pubmed
urn-nbn

Altmetric score

doi
pubmed
urn-nbn
Total: 297 hits
CiteExportLink to record
Permanent link

Direct 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