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An additional ionic bond suggested by molecular modelling of TEM-2 might induce a slight discrepancy between
E B Chaïbi1, S Farzaneh, J Péduzzi
1Muséum National Histoire Naturelle, CNRS URA 401, Paris, France.
FEMS Microbiology Letters
|October 1, 1996
Abstract:
The plasmid-mediated TEM-1 and TEM-2 beta-lactamases are the most commonly encountered among Gram-negative bacteria. They belong to molecular class A, and differ by one amino acid at position 39:TEM-1 have a glutamine and TEM-2 a lysine. Kinetic parameters (kcat and Km) and catalytic efficiency (kcat/Km) of TEM-1 and TEM-2 beta-lactamases are slightly, but significantly different. For all antibiotics except methicillin and cefazolin, the catalytic efficiency values of TEM-2 are clearly greater than that of TEM-1. Molecular modelling of TEM-2, when compared to that of TEM-1, showed an additional ionic bond between Lys-39 and Glu-281.