Analysis of pYC2, a cryptic plasmid in Lactobacillus sakei BM5 isolated from kimchi

Analysis of the structural properties of pYC2, a cryptic plasmid from Lactobacillus sakei BM5 isolated from kimchi, determined its length as 1,970 bp with a G + C content of 34%. The double-strand origin (dso) and single-strand origin (sso) of rolling-circle replicating plasmids were found in the nucleotide sequence of the pYC2 plasmid. Sequence analysis of pYC2 revealed that ORF 1 and ORF 2 showed high homology with the Cop and Rep proteins encoded by the pMV158 family of plasmids replicating via the rolling-circle mechanism. pYC2 also replicates by this mechanism, as confirmed by Southern hybridization analysis.