PURIFICATION AND STRUCTURE OF MUTACIN B-NY266 - A NEW LANTIBIOTIC PRODUCED BY STREPTOCOCCUS-MUTANS

Mutacins are bactericidal substances of proteinaceous nature produced by Streptococcus mutans. Lantibiotics are antibacterial substances con taining post-translationally modified amino acids such as lanthionine. Mutacin B-Ny266 was purified from the cell pellet of S. mutans strain Ny266 by ethanol extraction at pH 2.0 followed by reversed-phase chro matography (Sep-Pak(R) cartridge) and by HPLC on a C-18 column. The me an purification factor was 3240+/-81 and the mean yield was 1.0 +/- 0. 1%. Molecular mass of mutacin B-Ny266 as determined by mass spectrosco py is 2270.29+/-0.21 Da. The amino acid sequence of the purified activ e fraction was obtained by Edman degradation after treatment with alka line ethanethiol. Twenty-one amino acids were detected in this analysi s. Mutacin B-Ny266 belongs to the type A lantibiotics. The proposed se quence is: F-K-(A) under bar-W-U-F-(A) under bar-<(Abu)under bar>-P-G- (A) under bar-A-K-O-G-(A) under bar-F-N-(U) under bar-Y-(A) under bar. The molecule differs from that of epidermin/staphylococcin 1580 and g allidermin at positions 1, 2, 4, 5 and 6. (C) 1997 Federation of Europ ean Biochemical Societies.