2y75
From Proteopedia
The Structure of CymR (YrzC) the Global Cysteine Regulator of B. subtilis
Structural highlights
FunctionCYMR_BACSU Master repressor of cysteine metabolism in B.subtilis. Controls the expression of genes involved either in cysteine synthesis from sulfide (cysK), sulfonates (ssu), or methionine (mccAB) or in cystine uptake (tcyP). Activity of CymR is positively regulated by CysK in response to cysteine availability. When cysteine is present, the pool of O-acetylserine (OAS) is low, which leads to the formation of a CymR-CysK complex and transcriptional repression of the CymR regulon occurs. In the absence of cysteine, the OAS pool is high and the CymR-CysK complex is mostly dissociated, leading to a faster dissociation of CymR from its DNA targets and the lifting of CymR-dependent repression.[1] [2] Publication Abstract from PubMedThe global regulator CymR represses the transcription of a large set of genes involved in cystine uptake and cysteine biosynthesis in Bacillus subtilis and Staphylococcus aureus. This repressor belongs to the widespread and poorly characterized Rrf2 family of regulators. The crystal structure of CymR from B. subtilis reveals a biologically active dimer, where each monomer folds into two tightly packed domains: a DNA-binding domain, which houses a winged helix-turn-helix (wHTH) motif; and a long dimerization domain, which places the wHTH motifs at the extremes. This architecture explains how these small regulators can span 23-27-bp DNA targets. The wHTH motif of CymR resembles those of the GntR superfamily of regulators, such as FadR and HutC. Superimposing the FadR wHTH motifs bound to their DNA fragments onto the wHTH motifs of the CymR dimer structure suggests that the DNA target and/or the protein must undergo some conformational changes upon binding. The CymR structure also hints at a possible location of the Fe-S centre associated with several Rrf2-type regulators. Structured digital abstract * CymR binds to CymR by x-ray crystallography (View Interaction 1, 2). Insights into the Rrf2 repressor family - the structure of CymR, the global cysteine regulator of Bacillus subtilis.,Shepard W, Soutourina O, Courtois E, England P, Haouz A, Martin-Verstraete I FEBS J. 2011 Aug;278(15):2689-701. doi: 10.1111/j.1742-4658.2011.08195.x., Epub 2011 Jul 1. PMID:21624051[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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