Purification and identification of a peptide antibiotic produced by Lactococcus lactis IO-1

• Published in: Journal of the Faculty of Agriculture, Kyushu University Vol. 40; no. 1-2
• Main Authors: Matsusaki, H. (Kyushu Univ., Fukuoka (Japan). Faculty of Agriculture), Endo, N, Sonomoto, K, Ishizaki, A
• Format: Journal Article
• Language: English
• Published: 01.12.1995
• Subjects: ANTIBIOTICOS; ANTIBIOTIQUE; IDENTIFICACION; IDENTIFICATION; LACTOCOCCUS LACTIS; PEPTIDE; PEPTIDOS; PURIFICACION; PURIFICATION
• ISSN: 0023-6152
• DOI: 10.5109/24095

Lactococcus lactis IO-1. which ws isolated in our laboratory, produces a new peptide antibiotic that was proposed previously to be a variant of nisin. Further purification to homogeneity of the peptide from the culture supernatant allowed us to identify it was a derivative of natural nisin, designated nisin Z, as follows. The culture supernatant of L. lactis IO-1 inhibited the growth of various Grampositive bacteria but no that of a nisin A-producing strain, L. lactis NCDO 497, as shown also in the case of a commercial preparation of nisin (nisin A). A nisin-like peptide antibiotic produced by L. lactis IO-1 was efficiently purified by a rapid and simple procedure, which included acid treatment, ammonium sulfate precipitation, cation-exchange chromatography and reversed-phase high performance liquid chromatography. The specific activity of the purified antibiotic was 122-fold greater than that of the starting material and the recovery was 24%. The molecular mass of this peptide antibiotic was 3337.9 by fast atom bombardment - mass spectrometry (FAB-MS). Amino acid FAB-MS and 1H-NMR analyses of the peptide antibiotic purified from strain IO-1, and the deduced amino acid sequence of the precursor peptide showed that it differed from nisin A by a single amino acid substitution (His27 - Asn27) and was identical to nisin Z, a natural variant of nisin