PURIFICATION AND CHARACTERIZATION OF STAPHYLOCOCCIN BACR1, A BROAD-SPECTRUM BACTERIOCIN

The bacteriocin BacR1 was purified from culture supernatant of Staphyl ococcus aureus UT0007 by sequential ammonium sulfate precipitation, ca tion-exchange chromatography, and C-4 reverse-phase chromatography ste ps, Mass spectrographic analysis indicated that the purified peptide h as a molecular mass of 3,338 Da, It is resistant to environmental cond itions, retaining full biological activity after exposure to pH extrem es (pHs 3 to 11), heating at 95 degrees C for 15 min, and exposure to strong chaotropic agents. BacR1 was destroyed with a complete loss of biological activity after digestion with trypsin and proteinase K, Ami no acid sequence analysis revealed a high concentration of Asx, Gly, a nd Pro residues and a high proportion of hydrophobic amino acids, The peptide is bactericidal and kills in a dose-dependent manner, but it d oes not lyse log-phase cells of Corynebacterium renale, the routine in dicator organism for bacteriocin assay, A specific receptor for bindin g was detected on sensitive cells but not on insensitive cells, Compet ition assays showed that UV-inactivated cells could protect susceptibl e cells from antibacterial action, A partial inhibitory spectrum revea led that organisms from the following genera are susceptible: Staphylo coccus, Streptococcus, Corynebacterium, Haemophilus, Bordetella, Morax ella, Pasteurella, Neisseria, and Bacillus.