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.
Arakawa
K
K
Laboratory of Animal Products Chemistry, Graduate School of Agricultural Science, Tohoku University, Sendai, Japan.
Kawai
Y
Y
Ito
Y
Y
Nakamura
K
K
Chujo
T
T
Nishimura
J
J
Kitazawa
H
H
Saito
T
T
D001430:Bacteriocins / Q000737:chemistry* / Q000302:isolation & purification*; D002851:Chromatography, High Pressure Liquid; D007778:Lactobacillus / Q000737:chemistry; D013058:Mass Spectrometry
D001430:Bacteriocins; C096679:gassericin A