3fgp
From Proteopedia
2.05 a Crystal Structure of CysM from Mycobacterium Tuberculosis - Open and Closed Conformations
Structural highlights
FunctionCYSM_MYCTU Catalyzes the formation of a covalent CysO-cysteine adduct via a sulfur transfer, using the thiocarboxylated sulfur carrier protein CysO-COSH as sulfur donor and O-phospho-L-serine (OPS) as sulfur acceptor. Can also use sodium sulfide as sulfur donor in vitro, albeit with less efficiency, but not thiosulfate or thio-nitro-benzoate. O-acetylserine (OAS) is a very poor substrate in comparison with OPS. May be of particular importance for cysteine biosynthesis in the persistent phase of M.tuberculosis.[1] [2] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedA new crystal structure of the dimeric cysteine synthase CysM from Mycobacterium tuberculosis reveals an open and a closed conformation of the enzyme. In the closed conformation the five carboxy-terminal amino acid residues are inserted into the active site cleft. Removal of this segment results in a decreased lifetime of the alpha-aminoacrylate reaction intermediate, an increased sensitivity to oxidants such as hydrogen peroxide, and loss of substrate selectivity with respect to the sulfur carrier thiocarboxylated CysO. These results highlight features of CysM that might be of particular importance for cysteine biosynthesis under oxidative stress in M. tuberculosis. The C-terminal of CysM from Mycobacterium tuberculosis protects the aminoacrylate intermediate and is involved in sulfur donor selectivity.,Agren D, Schnell R, Schneider G FEBS Lett. 2009 Jan 22;583(2):330-6. Epub 2008 Dec 26. PMID:19101553[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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