Open AccessCharacterization of the active‐site residues asparagine 167 and lysine 161 of the IMP‐1 metallo β‐lactamase
Author(s) -
Haruta Shin,
Yamamoto Elise Tie,
Eriguchi Yoshiro,
Sawai Tetsuo
Publication year - 2001
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 - 10.1111/j.1574-6968.2001.tb10587.x
Subject(s) - asparagine , lysine , active site , aspartic acid , site directed mutagenesis , enzyme , chemistry , stereochemistry , alanine , biochemistry , mutagenesis , mutant , amino acid , gene
The roles of lysine at position 161 and asparagine at position 167 in IMP‐1 metallo β‐lactamase were studied by site‐directed mutagenesis. These residues are highly conserved in metallo β‐lactamases and are thought to be present in the active‐site cavity. Mutant enzymes with alanine or aspartic acid at position 167 showed almost the same properties as the wild‐type enzyme. Kinetic parameters for the mutant enzymes differing at position 161 indicated that the positive charge of lysine 161 is required for electrostatic interaction with the carboxyl moiety of the substrate, i.e. C‐3 of penicillins or C‐4 of cephalosporins.