Conservation of the major cold shock protein in lactic acid bacteria

Primers designed from consensus regions of the major cold shock gene of different bacterial species were used in PCR amplification of Lactic Acid Bacteria (LAB). An appropriately-sized PCR product was obtained from Lactococcus lactis subsp. lactis LL43-1 and MG1363; Lactococcus lactis subsp. cremoris LC10-1, LC11-1, and LC12-1; Streptococcus thermophilus ST1-1; Enterococcus faecalis EF1-1; Lactobacillus acidophilus LA1-1; Lactobacillus helveticus LH1-1; Pediococcus pentosaceus PP1-1; and Bifidobacterium animalis BA1-1. The PCR products were cloned and sequenced. The deduced amino acid sequences displayed high sequence similarity with the major cold shock proteins of Escherichia coli and Bacillus subtilis and the human Y-box factor. The amino acid residues of the cold shock domain implicated in nucleic acid binding in several unrelated species were also highly conserved in the LAB strains. It is possible, therefore, that this protein in LAB may also act as a transcriptional enhancer to other cold shock genes and/or act as an RNA chaperone unwinding tightly folded RNA molecules.