Analysis on characteristics of metalloprotease genes in Ralstonia mannitolilytica strain

Objective To detect the metalloprotease genes in the clinical isolates of R. mannitolilytica, and analyze the structural characteristics of the encoding proteins. Methods DNA from clinical isolates of R. mannitolilytica was extracted by Axygen bacterial genome extraction kit. Metalloprotease genes-based PCR detection method was established. BLAST was used to compare the gene sequence. CDD, MEROPS, SWISS-MODEL, CDTree, TMHMM and SignalP 4.1 were used to analyze encoding proteins online. Results The R. mannitolilytica clinical strain contained RS-MP48 gene and RS-MP50 gene of M48 superfamily and S2P-M50 superfamily, respectively. The genes were consistent with the reported genes (WP_045785189.1 and WP_045786756.1) in R. mannitolilytica strain SN82F48 (identity=100%) . Bioinformatics research showed that RS-MP48 contained one conserved domain of M48 metalloprotease superfamily and four transmembrane structures, and had highest homology with M48 metalloprotease, Zinc dependent protease of Methylobacillus flagellatus KT and Zinc dependent protease of Pseudomonas aeruginosa with 99% identity; while it only had 33% homology with heat shock protein in Streptomyces coelicolor and 32% homology with protease in Microcystis aeruginosa. RS-MP50 contained two conserved domains of S2P-M50 superfamily and four transmembrane structures with several membrane binding regions, and had highest homology with RseP in R.mannitolilytica with 99% identity; while it had 92% homology with RseP in Ralstonia sp. A12 and protease regulator in Ralstonia sp. NFACC01, as well as only 39% homology with NMB0183 protein in Neisseria meningitidis MC58 and 38% homology with Zinc dependent degrading enzyme in Shewanella oneidensis MR-1. Conclusions R. mannitolilytica is an emerging bacterial pathogen that leads to human infectious diseases. In this study, there is a metalloprotease gene in the clinical isolate of R. mannitolilytica and its encoded protein may be a potential virulence factor. Key words: Metalloproteases; Ralstonia mannitolilytica; Gene characteristics; Bioinformatics