Abstract : Several enzymes have evolved as sensors in signal transduction pathways to control gene expression, thereby allowing bacteria to adapt efficiently to environmental changes. We recently identified the master regulator of cysteine metabolism in Bacillus subtilis, CymR, which belongs to the poorly characterized Rrf2 family of regulators. We now report that the signal transduction mechanism controlling CymR activity in response to cysteine availability involves the formation of a stable complex with CysK, a key enzyme for cysteine biosynthesis. We carried out a comprehensive quantitative characterization of this regulator-enzyme interaction by surface plasmon resonance and analytical ultracentrifugation. We also showed that O-acetylserine plays a dual role as a substrate of CysK and as an effector modulating the CymR-CysK complex formation. The ability of B. subtilis CysK to bind to CymR appears to be correlated to the loss of its capacity to form a cysteine synthase complex with CysE. We propose an original model, supported by the determination of the intracellular concentrations of the different partners, by which CysK positively regulates CymR in sensing the bacterial cysteine pool.
https://hal-pasteur.archives-ouvertes.fr/pasteur-03525653 Contributor : Patrick EnglandConnect in order to contact the contributor Submitted on : Friday, January 14, 2022 - 5:15:57 AM Last modification on : Thursday, April 7, 2022 - 10:10:30 AM Long-term archiving on: : Friday, April 15, 2022 - 6:15:38 PM
Catherine Tanous, Olga Soutourina, Bertrand Raynal, Marie-Françoise Hullo, Peggy Mervelet, et al.. The CymR Regulator in Complex with the Enzyme CysK Controls Cysteine Metabolism in Bacillus subtilis. Journal of Biological Chemistry, American Society for Biochemistry and Molecular Biology, 2008, 283 (51), pp.35551 - 35560. ⟨10.1074/jbc.m805951200⟩. ⟨pasteur-03525653⟩