A MURC GENE IN PORPHYROMONAS-GINGIVALIS-381

The gene encoding a 51 kDa polypeptide of Porphyromonas gingivalis 381 was isolated by immunoblotting using an antiserum raised against P. g ingivalis alkaline phosphatase. DNA sequence analysis of a 2.5 kb DNA fragment containing a gene encoding the 51 kDa protein revealed one co mplete and two incomplete ORFs, Database searches using the FASTA prog ram revealed significant homology between the P. gingivalis 51 kDa pro tein and the MurC protein of Escherichia coil, which functions in pept idoglycan synthesis. The cloned 51 kDa protein encoded a functional pr oduct that complemented an E. coil murC mutant. Moreover, the ORF just upstream of murC coded for a protein that was 31% homologous with the E. coli MurG protein. The ORF just downstream of murC coded for a pro tein that was 17% homologous with the Streptococcus pneumoniae penicil lin-binding protein 2B (PBP2B), which functions in peptidoglycan synth esis and is responsible for antibiotic resistance. These results sugge st that P. gingivalis contains a homologue of the E. coli peptidoglyca n synthesis gene murC and indicate the possibility of a cluster of gen es responsible for cell division and cell growth, as in the E. coil mr a region.