Accueil > Publications > Recherche par années > Années 1990 > 1994

Jamin, M ; Damblon, C ; Bauduinmisselyn, AM ; Durant, F ; Roberts, GCK ; Charlier, P ; Llabres, G ; Frère, JM

Direct NMR evidence for substrate-induced conformational-changes in a ß-lactamase

Biochemical Journal 301 199-203

par Administrateur - publié le

Abstract :

Cefoxitin and other ß-lactam antibiotics with a methoxy group on the a-face behave as very poor substrates of the Bacillus licheniformis ß-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.