Open AccessIdentification of a triad of arginine residues in the active site of the ArsC arsenate reductase of plasmid R773
Author(s) -
Shi Jin,
Mukhopadhyay Rita,
Rosen Barry P
Publication year - 2003
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1016/s0378-1097(03)00695-5
Subject(s) - active site , arginine , biochemistry , site directed mutagenesis , arsenate , mutant , mutagenesis , binding site , chemistry , biology , enzyme , amino acid , arsenic , organic chemistry , gene
ArsC from plasmid R773 catalyzes reduction of arsenate in Escherichia coli . Arg‐60, Arg‐94 and Arg‐107 are near the active site residue Cys‐12, suggesting that they form an anion binding pocket in the active site and/or participate in catalysis. These three arginine residues were altered to a variety of other residues by site‐directed mutagenesis. Only mutants with arginine‐to‐lysine substitutions conferred arsenate resistance in vivo, although purified R60A, R60E, R60K exhibited varying levels of enzymatic activity. The data support the hypothesis that this triad of arginine residues is involved in arsenate binding and transition‐state stabilization.