Anti-Bacterial Agents; Bacillus/enzymology; Cefoxitin; Circular Dichroism; Crystallography; Kinetics; Magnetic Resonance Spectroscopy; Protein Conformation; Substrate Specificity; beta-Lactamases/chemistry/metabolism
Abstract :
[en] Cefoxitin and other beta-lactam antibiotics with a methoxy group on the alpha-face behave as very poor substrates of the Bacillus licheniformis beta-lactamase. The kinetic properties of the enzyme-cefoxitin system made it theoretically suitable for a detailed structural study of the acyl-enzyme. Unfortunately, soaking the crystals in cefoxitin solution did not allow detection of a crystalline acyl-enzyme complex. In contrast, direct observation by n.m.r. of the stable acyl-enzyme formed with cefoxitin and moxalactam indicated clear modifications of the enzyme structure, which were reflected in the aromatic and high-field methyl regions of the spectrum. The return to the initial free enzyme spectrum was concomitant with the hydrolysis of the acyl-enzyme, the process being slow enough to allow multidimensional n.m.r. experiments.
Disciplines :
Biochemistry, biophysics & molecular biology
Author, co-author :
Jamin, M.
Damblon, Christian ; Université de Liège - ULiège > Département de chimie (sciences) > Chimie biologique structurale
Bauduin-Misselyn, A. M.
Durant, F.
Roberts, G. C.
Charlier, Paulette ; Université de Liège - ULiège > Département des sciences de la vie > Cristallographie des macromolécules biologiques
Llabres, Gabriel ; Université de Liège - ULiège > Département de physique > Département de physique
Frère, Jean-Marie ; Université de Liège - ULiège > Centre d'ingénierie des protéines
Language :
English
Title :
Direct n.m.r. evidence for substrate-induced conformational changes in a beta-lactamase.