The pcd Gene Encoding Piperideine-6-Carboxylate Dehydrogenase Involved in Biosynthesis of α-Aminoadipic Acid Is Located in the Cephamycin Cluster of Streptomyces clavuligerus

Three open reading frames (ORFs) have been located downstream of cefE in the cephamycin C gene cluster of Streptomyces clavuligerus. ORF13 (pcd) encodes a 496-amino-acid protein (molecular weight [MW], 52,488) with an N-terminal amino acid sequence identical to that of pure piperideine-6-carboxylate dehydrogenase. ORF14 (cmcT) encodes a 523-amino-acid protein (MW, 54,232) analogous to Streptomyces proteins for efflux and resistance to antibiotics. ORF15 (pbp74) encodes a high molecular weight penicillin-binding protein (MW, 74,094).