Product-substrate engineering by bacteria: Studies on clavaminate synthase, a trifunctional dioxygenase

Evidence is presented that clavaminate synthase (CS) catalyses three oxidat ive reactions in the clavulanic acid biosynthetic pathway. The first CS cat alysed step (hydroxylation) is separated from the latter two (oxidative cyc lisation and desaturation) by the action of a hydrolytic enzyme, proclavami nate amidinohydrolase, which modifies (or 'mutates') the sidechain of the p roduct of the first reaction thereby converting it into a substrate for the second CS catalysed reaction. (C) 1999 Elsevier Science Ltd. All rights re served.