Journal
MICROBIOLOGY-SGM
Volume 148, Issue -, Pages 3347-3352Publisher
SOC GENERAL MICROBIOLOGY
DOI: 10.1099/00221287-148-11-3347
Keywords
rumen; lactic acid bacteria; purification; N-terminal amino acids
Categories
Ask authors/readers for more resources
Previous work indicated that Streptococcus bovis HC5 had significant antibacterial activity, and even nisin-resistant S. bovis JB1 cells could be strongly inhibited. S. bovis HC5 inhibited a variety of Gram-positive bacteria and the spectrum of activity was similar to monensin, a commonly used feed additive. The crude extracts (ammonium sulfate precipitation) were inactivated by Pronase E and trypsin, but the activity was resistant to heat, proteinase K and alpha-chymotrypsin. Most of the antibacterial activity was cell associated, but it could be liberated by acidic NaCl (100 mM, PH 2.0) without significant cell lysis. When glycolysing S. bovis JB1 cells were treated with either crude or acidic NaCl extracts, intracellular potassium declined and this result indicated the antibacterial activity was mediated by a pore-forming peptide. The peptide could be purified by HPLC and matrix-assisted laser desorption ionization time-of-flight analysis indicated that it had a molecular mass of approximately 2440 Da. The terminal amino acid sequence was VGXRYASXPGXSWKYVXF. The unnamed amino acid residues (designated by X) had approximately the same position as dehydroalanines found in some lantibiotics, but samples that were reduced and alkylated prior to Edman degradation did not have cysteine residues. The only other bacteriocin that had significant similarity was the lantibiotic precursor of Streptococcus pyogenes SF370, but the identity was only 55%. Based on these results, the bacteriocin of S. bovis HC5 appears to be novel and the authors now designate it as bovicin HC5.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available