Purification and partial characterization of lactacin F, a bacteriocin produced by Lactobacillus acidophilus 11088.
Lactacin F, a bacteriocin produced by Lactobacillus acidophilus 11088 (NCK88), was purified and characterized. Lactacin F is heat stable, proteinaceous, and inhibitory to other lactobacilli as well as Enterococcus faecalis. The bacteriocin was isolated as a floating pellet from culture supernatants brought to 35 to 40% saturation with ammonium sulfate. Native lactacin F was sized at approximately 180 kDa by gel filtration. Column fractions having lactacin F activity were examined by electron microscopy and contained micelle-like globular particles. Purification by ammonium sulfate precipitation, gel filtration, and high-performance liquid chromatography resulted in a 474-fold increase in specific activity of lactacin F. The purified bacteriocin was identified as a 2.5-kDa peptide by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The lactacin F peptide retained activity after extraction from SDS-PAGE gel slices, confirming the identity of the 2.5-kDa peptide. Variants of NCK88 that failed to exhibit lactacin F activity did not produce the 2.5-kDa band. Sequence analysis of purified lactacin F identified 25 N-terminal amino acids containing an arginine residue at the N terminus. Composition analysis indicates that lactacin F may contain as many as 56 amino acid residues.
Muriana
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PM
Department of Food Science, North Carolina State University, Raleigh 27695-7624.
Klaenhammer
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D000595:Amino Acid Sequence; D001430:Bacteriocins / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000302:isolation & purification*; D003902:Detergents / Q000494:pharmacology; D006867:Hydrolases / Q000494:pharmacology; D007779:Lactobacillus acidophilus / Q000032:analysis* / Q000235:genetics; D008969:Molecular Sequence Data; D014462:Ultrafiltration
D001430:Bacteriocins; D003902:Detergents; C067573:lactacin F; D006867:Hydrolases