Open AccessAn additional ionic bond suggested by molecular modelling of TEM‐2 might induce a slight discrepancy between catalytic properties of TEM‐1 and TEM‐2 β‐lactamases
Author(s) -
Chaïbi El Bachir,
Farzaneh Sedigheh,
Péduzzi Jean,
Barthélémy Michel,
Labia Roger
Publication year - 1996
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.1574-6968.1996.tb08470.x
Subject(s) - catalysis , enzyme kinetics , chemistry , ionic bonding , lysine , glutamine , stereochemistry , nuclear chemistry , amino acid , biochemistry , organic chemistry , active site , ion
The plasmid‐mediated TEM‐1 and TEM‐2 β‐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 ( k cat and K m ) and catalytic efficiency ( k cat / K m ) of TEM‐1 and TEM‐2 β‐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.