Identification of the bacteriocin Lcn972A- producing bacteria and the cloning and sequence analysis of its bacteriocin gene

Objective: In this study, bacteriocin Lcn972A- producing bacteria were screened from 63 strains of lactic acid bacteria isolated from Pleurotus eryngii fruit body and Thallus Laminariae. Subsequently, gene for this bacteriocin was cloned by PCR methods and analyzed by bioinformatics tools. Method: Primers were designed based on the results of bioinformatics analysis of reported genes for lcn972 A. Subsequently, genes for Lcn927 A were isolated from the genomic DNA of 63 strains of lactic acid bacteria respectively. Finally, the nucleotide sequence and predicted protein sequence were analyzed by a series of bioinformatics tools. Result: Genes for Lcn927 A were isolated from 15 genomic samples among 63 strains of Lactic acid bacteria.Two of the positive stains were characterized as Lactococcus lactis from Pleurotus eryngii fruitbody A15 and Thallus Laminariae CX2. The result of sequencing showed that the full length of the Lcn927 A gene was 276 bp, which coded for 91 amino acid residues, with molecular weight of 22843.3 u, theoretical PI of 5.33, hydrophilic amino acid, the secondary structure of protein consist of α- helix, random coil and extended strand.Conclusion: The nucleotide sequence and predicted protein sequence of present Lcn927 A gene of Lactococcus lactis A15 and CX2 isolated from Pleurotus eryngii fruitbody and Thallus Laminariae were different from those that hadbeen publicly reported, and the antimicrobial properties of this gene need to be identified in the future study.