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Thiol redox switches regulate the oligomeric state of cyanobacterial Rre1, RpaA and RpaB response regulators.

Published version
Peer-reviewed

Change log

Authors

Ibrahim, Iskander M  ORCID logo  https://orcid.org/0000-0002-2744-6307
Rowden, Stephen JL 
Cramer, William A 
Howe, Christopher J 
Puthiyaveetil, Sujith 

Abstract

Cyanobacteria employ two-component sensor-response regulator systems to monitor and respond to environmental challenges. The response regulators RpaA, RpaB, Rre1 and RppA are integral to circadian clock function and abiotic stress acclimation in cyanobacteria. RpaA, RpaB and Rre1 are known to interact with ferredoxin or thioredoxin, raising the possibility of their thiol regulation. Here, we report that Synechocystis sp. PCC 6803 Rre1, RpaA and RpaB exist as higher-order oligomers under oxidising conditions and that reduced thioredoxin A converts them to monomers. We further show that these response regulators contain redox-responsive cysteine residues with an Em7 around -300 mV. These findings suggest a direct thiol modulation of the activity of these response regulators, independent of their cognate sensor kinases.

Description

Funder: Spicer Consulting Ltd

Keywords

Hik2, RpaA, RpaB, Rre1, TrxA, thiol regulation, Bacterial Proteins, Cyanobacteria, Gene Expression Regulation, Bacterial, Oxidation-Reduction, Sulfhydryl Compounds, Synechocystis, Thioredoxins

Journal Title

FEBS Lett

Conference Name

Journal ISSN

0014-5793
1873-3468

Volume Title

Publisher

Wiley
Sponsorship
Engineering and Physical Sciences Research Council (EP/F047940/1)
Biotechnology and Biological Sciences Research Council (BB/L014130/1)
BBSRC (BB/T010525/1)