Change search
ReferencesLink to record
Permanent link

Direct link
Thioredoxin targets of the plant chloroplast lumen and their implications for plastid function
Umeå University, Faculty of Science and Technology, Department of Chemistry.
Instituto de Bioquimica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas – Universidad de Sevilla, Spain.
Department of Biochemistry, Molecular Protein Science, Lund University, Lund, Sweden.
Instituto de Bioquimica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas – Universidad de Sevilla, Spain.
Show others and affiliations
2010 (English)In: Proteomics, ISSN 1615-9861, Vol. 10, no 5, 987-1001 p.Article in journal (Refereed) Published
Abstract [en]

The light-dependent regulation of stromal enzymes by thioredoxin-catalysed disulphide/dithiol exchange is known as a classical mechanism for control of chloroplast metabolism. Recent proteome studies show that thioredoxin targets are present not only in the stroma but in all chloroplast compartments, from the envelope to the thylakoid lumen. Thioredoxin-mediated redox control appears to be a common feature of important pathways, such as the Calvin cycle, starch synthesis and tetrapyrrole biosynthesis. However, the extent of thiol-dependent redox regulation in the thylakoid lumen has not been previously systematically explored. In this study, we addressed thioredoxin-linked redox control in the chloroplast lumen of Arabidopsis thaliana.Using complementary proteomics approaches, we identified 19 thioredoxin target proteins, thus covering more than 40 percent of the currently known lumenal chloroplast proteome. We show that the redox state of thiols is decisive for degradation of the extrinsic PsbO1 and PsbO2 subunits of photosystem II. Moreover, disulphide reduction inhibits activity of the xanthophyll cycle enzyme violaxanthin de-epoxidase, which participates in thermal dissipation of excess absorbed light. Our results indicate that redox-controlled reactions in the chloroplast lumen play essential roles in the function of photosystem II and the regulation of adaptation to light intensity.

Place, publisher, year, edition, pages
Wiley InterScience , 2010. Vol. 10, no 5, 987-1001 p.
Keyword [en]
D1-processing, Disulphide, Immunophilin, Pentapeptide protein, Plant proteomics, Violaxanthin de-epoxidase
National Category
Chemical Sciences
URN: urn:nbn:se:umu:diva-30831DOI: 10.1002/pmic.200900654ISI: 000275790700009PubMedID: 20049866OAI: diva2:292253
Available from: 2010-02-05 Created: 2010-01-18 Last updated: 2012-08-30Bibliographically approved
In thesis
1. The chloroplast lumen: New insights into thiol redox regulation and functions of lumenal proteins
Open this publication in new window or tab >>The chloroplast lumen: New insights into thiol redox regulation and functions of lumenal proteins
2012 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

In higher plants oxygenic photosynthesis primarily takes place in the chloroplasts of leaves. Within the chloroplasts is an intricate membrane system, the thylakoid membrane, which is the site of light harvesting and photosynthetic electron transport. Enclosed by this membrane is the lumen space, which initially was believed to only contain a few proteins, but now is known to house a distinct set of >50 proteins, many for which there is still no proposed function. The work presented in this thesis is focused on understanding the functions of the proteins in the lumen space. Using proteomic methods, we investigated first the regulation of lumenal proteins by light and secondly by dithiol-disulphide exchange, mediated by the disulphide reductase protein thioredoxin. We furthermore performed structural and functional studies of the lumenal pentapeptide repeat proteins and of the PsbP-domain protein PPD6. When studying the diurnal expression pattern of the lumen proteins, using difference gel electrophoresis, we observed an increased abundance of fifteen lumen protein in light-adapted Arabidopsis thaliana plants. Among these proteins were subunits of the oxygen evolving complex, plastocyanin and proteins of unknown function. In our analysis of putative lumenal targets of thioredoxin, we identified nineteen proteins, constituting more than 40 % of the lumen proteins observable by our methods. A subset of these putative target proteins were selected for further studies, including structure determination by x-ray crystallography. The crystal structure of the pentapeptide repeat protein TL15 was solved to 1.3 Å resolution and further biochemical characterization suggested that it may function as a novel type of redox regulated molecular chaperone in the lumen. PPD6, a member of the PsbP-family of proteins, which is unique in that it possesses a conserved disulphide bond not found in any other PsbP-family protein, was also expressed, purified and crystallized. A preliminary x-ray analysis suggests that PPD6 exists as a dimer in the crystalline state and binds zinc ions. The high representation of targets of thioredoxin among the lumen proteins, along with the characterization of the pentapeptide repeat protein family, implies that dithiol-disulphide exchange reactions play an important role in the thylakoid lumen of higher plants, regulating processes such as photoprotection, protein turnover and protein folding.

Place, publisher, year, edition, pages
Umeå: Umeå universitet, 2012. 65 p.
Photosynthesis, thylakoid lumen, thioredoxin, pentapeptide repeat, proteomics
National Category
Biochemistry and Molecular Biology
Research subject
urn:nbn:se:umu:diva-58423 (URN)978-91-7459-467-6 (ISBN)
Public defence
2012-09-21, KBC huset, KB3B1, Umeå Universitet, Umeå, 09:00 (English)
Available from: 2012-08-31 Created: 2012-08-29 Last updated: 2012-08-30Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full textPubMed

Search in DiVA

By author/editor
Hall, MichaelSchröder, WolfgangKieselbach, Thomas
By organisation
Department of Chemistry
Chemical Sciences

Search outside of DiVA

GoogleGoogle Scholar
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Altmetric score

Total: 193 hits
ReferencesLink to record
Permanent link

Direct link