HPLC purification and re-evaluation of chemical identity of two circular bacteriocins, gassericin A and reutericin 6.
OBJECTIVE
The study aimed for the complete purification and recharacterization of the highly hydrophobic circular bacteriocins, gassericin A and reutericin 6.


RESULTS
Gassericin A and reutericin 6 were purified to homogeneity using previously described method and reverse-phase HPLC with an octyl column and eluents of aqueous acetonitrile and 2-propanol. Mass analysis, N-terminal sequencing and bacteriocin assay of the HPLC-purified bacteriocins showed the two bacteriocins had identical seamless circular structures with the same m/z value (5651) of [M + H](+) and both had the same specific activity. D/L-amino acid composition analysis using two distinct methods with the chiral fluorescent derivatization reagents (+)-1-(9-fluorenyl)ethyl chloroformate and O-phthalaldehyde/N-acetyl-L-cystein revealed neither gassericin A nor reutericin 6 contained D-alanine residues contrary to our previous results.


CONCLUSIONS
Purified gassericin A and reutericin 6 are chemically identical circular molecules containing no D-alanine residues.


CONCLUSIONS
The HPLC conditions developed in this study will facilitate advanced purification and correct characterization of other highly hydrophobic bacteriocins.
Laboratory of Animal Products Chemistry, Graduate School of Agricultural Science, Tohoku University, Sendai, Japan.
K
K
Arakawa
Y
Y
Kawai
Y
Y
Ito
K
K
Nakamura
T
T
Chujo
J
J
Nishimura
H
H
Kitazawa
T
T
Saito
D001430:Bacteriocins / Q000737:chemistry* / Q000302:isolation & purification*; D002851:Chromatography, High Pressure Liquid; D007778:Lactobacillus / Q000737:chemistry; D013058:Mass Spectrometry
D001430:Bacteriocins; C096679:gassericin A