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The C‐terminal of CysM from Mycobacterium tuberculosis protects the aminoacrylate intermediate and is involved in sulfur donor selectivity
Author(s) -
Ågren Daniel,
Schnell Robert,
Schneider Gunter
Publication year - 2009
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/j.febslet.2008.12.019
Subject(s) - chemistry , cysteine , selectivity , hydrogen peroxide , mycobacterium tuberculosis , sulfur , enzyme , substrate (aquarium) , stereochemistry , biochemistry , catalysis , tuberculosis , organic chemistry , biology , medicine , ecology , pathology
A 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 α‐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 .