Implication of Ile-69 and Thr-182 residues in kinetic characteristics of IRT-3 (TEM-32) beta-lactamase.
The substitution of a methionine for an isoleucine at position 69 (Met69Ile), which causes inhibitor resistance to TEM-type beta-lactamases (IRT-3 and IRT-I69), altered the positions of the Asn-170 and Glu-166 side chains as well as the position of the catalytic water molecule. A novel hydrogen bond between the hydroxyl of Thr-182 and the carbonyl of Glu-64 was expected to be responsible for the increase in the catalytic activity of the IST-T182 and IRT-3 enzymes compared with those of TEM-1 and IRT-169, respectively.
URA 401 Centre National de la Recherche Scientifique,-MNHN, Quimper, France.
S
S
Farzaneh
E B
EB
Chaibi
J
J
Peduzzi
M
M
Barthelemy
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Labia
J
J
Blazquez
F
F
Baquero
D002384:Catalysis; D002511:Cephalosporins / Q000378:metabolism; D007532:Isoleucine / Q000737:chemistry / Q000378:metabolism*; D007700:Kinetics; D010406:Penicillins / Q000378:metabolism; D013912:Threonine / Q000737:chemistry / Q000378:metabolism*; D001618:beta-Lactamases / Q000737:chemistry / Q000378:metabolism*
D002511:Cephalosporins; D010406:Penicillins; D007532:Isoleucine; D013912:Threonine; C104070:beta-lactamase IRT-3; D001618:beta-Lactamases