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Signal transduction by the global regulator RegB is mediated by a redox‐active cysteine
Author(s) -
Swem Lee R.,
Kraft Brian J.,
Swem Danielle L.,
Setterdahl Aaron T.,
Masuda Shinji,
Knaff David B.,
Zaleski Jeffrey M.,
Bauer Carl E.
Publication year - 2003
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1093/emboj/cdg461
Subject(s) - cysteine , biology , biochemistry , signal transduction , microbiology and biotechnology , redox , thioredoxin , biophysics , enzyme , chemistry , organic chemistry
All living organisms alter their physiology in response to changes in oxygen tension. The photosynthetic bacterium uses the RegB–RegA signal transduction cascade to control a wide variety of oxygen‐responding processes such as respiration, photosynthesis, carbon fixation and nitrogen fixation. We demonstrate that a highly conserved cysteine has a role in controlling the activity of the sensor kinase, RegB. In vitro studies indicate that exposure of RegB to oxidizing conditions results in the formation of an intermolecular disulfide bond and that disulfide bond formation is metal‐dependent, with the metal fulfilling a structural role. Formation of a disulfide bond in vitro is also shown to convert the kinase from an active dimer into an inactive tetramer state. Mutational analysis indicates that a cysteine residue flanked by cationic amino acids is involved in redox sensing in vitro and in vivo . These residues appear to constitute a novel ‘redox‐box’ that is present in sensor kinases from diverse species of bacteria.