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Antimicrobial peptides of Lactobacillus salivarius K4 isolated from chicken intestine

Papassara Sangtanoo^a, Kiattawee Choowongkomon^b, Wunrada Surat^a, Sunee Nitisinprasert^c, Anchanee Kubera^a,*

 
ABSTRACT:     Two cationic antimicrobial peptides, salvicin K (sal K) and antimicrobial-like bacteriocin β (alb β) from Lactobacillus salivarius K4 were isolated from chicken intestine. In the active form, each peptide contains 47 amino acids with 2 cysteine residues. The antimicrobial activity showed that sal K could inhibit the food pathogens Enterococcus faecalis JCM 5803, Lb. plantarum ATCC 14917, and Streptococcus sp. TISTR 1030. The alb β showed activity against E. faecalis JCM 5803, Leuconostoc mesenteroides subsp. mesenteroides JCM 6124, Lb. sakei TISTR 890, Lb. plantarum ATCC 14917, and Streptococcus sp. TISTR 1030. A high concentration of these bacteriocins was found to cause hemolysis in rat erythrocytes. Each peptide was predicted to have a mixed secondary structure of α-helix, β-sheet, and random coil structure with one disulphide bond. Two antimicrobial peptides were found to be unstructured in Tris-Cl pH 9. These two peptides adopted an α-helix conformation in 10% SDS micelles (to simulate the bacterial cell wall). In zwitterionic dodecylphosphocholine micelles and liposome, these two peptides adopted a β-sheet structure. The results suggest that the α-helix is an important conformation for these peptides to express their antimicrobial activity.

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* Corresponding author, E-mail: fsciacs@ku.ac.th

Received 13 Aug 2013, Accepted 14 Dec 2013