Identification and Characterization of the Genes for Malonate Catabolism from Klebsiella pneumoniae

A Klebsiella pneumoniae cosmid clone which confers Escherichia coli the ability to grow on malonate as sole carbon source was isolated. Studies of deletion and transposon insertion mutants have localized the functional region within a 10-kb DNA segment. Nucleotide sequence analysis of the region revealed seven major open reading frames which are transcribed in the same direction. The deduced amino acid sequences of these genes exhibit significant similarities with the enzymes involving in fatty acid biosynthesis including malonyl-CoA: acyl carrier protein transacylase and the .alpha. and .beta. components of transcarboxylase of the E. coli acetyl-CoA carboxylase. Malonate decarboxylating activity could be detected in both K. pneumoniae and the E. coli harboring the cosmid. The malonate decarboxylase was very unstable during purification and the activity could not be recovered by adding either acetyl-CoA or malonyl-CoA. The enzyme does not contain biotin and consequently is not inhibited by avidin. A role in fixation of a carboxyl group from malonate by the K. pneumoniae malonate utilization system is proposed.

Project ID:PB8309-1010
External Project ID:NSC83-0412-B182-059