EXPLOITING THE UNIQUE BIOPHYSICAL PROPERTIES OF BACTERIOCINS TO PURIFY BAC1829 FROM STAPHYLOCOCCUS-AUREUS KSI1829

Bac1829 from Staphylococcus aureus KSI1829 is a newly identified pepti de bacteriocin that inhibits a broad spectrum of bacteria. By taking a dvantage of its cationic and hydrophobic nature, a purification scheme was developed utilizing preparative isoelectric focusing and hydropho bic interaction chromatography. Due to a high pI value of approximatel y 9-10, 71% of the total Bac1829 activity was concentrated in two frac tions by preparative isoelectric focusing. Final purification by high performance liquid chromatography on a propyl hydrophobic interaction column resulted in a 136-fold purification with an increase in specifi c activity from 181 to 24,623 antimicrobial units (AU)/mg protein. A t otal of 14,848 AU of Bac1829 were purified using this revised procedur e, compared to 8702 AU as described previously. Mass spectrographic an alysis of the purified sample yielded a single peak of 6418 +/- 2 dalt ons. Since many bacteriocins possess similar biophysical attributes, t he purification scheme presented in this communication may be applicab le to those which have proven difficult to purify or have not been pur ified. (C) 1997 Academic Press.