Sequence diversity of the peptaibol antibiotic suzukacillin‐A from the mold Trichoderma viride

From the culture broth of the mold Trichoderma viride , strain 63 C‐I, the polypeptide antibiotic suzukacillin (SZ) was isolated. A peptide mixture named SZ‐A was obtained by crystallization from crude SZ. Individual peptides from SZ‐A were isolated by semipreparative HPLC and sequences were determined by HPLC‐ESI‐MS. The data confirm a general sequence of SZ‐A published previously and in addition establish the individual sequences of 15 acetylated eicosa peptides with C ‐terminal alcohols. The major peptide SZ‐A4 (21% of all peptides) shows the sequence: Ac‐Aib‐Ala‐Aib‐Ala‐Aib‐Ala 6 ‐Gln‐Aib‐Lx 9 ‐Aib‐Gly‐Aib 12 ‐Aib‐Pro‐Vx 15 ‐Aib‐Vx 17 ‐Gln‐Gln‐Fol. Amino acid exchanges of the peptaibol are located in position 6 (Ala/Aib), 9 (Vx/Lx), 12 (Aib/Lx), 17 (Aib/Vx) and possibly at position15 (Val/Iva) (uncommon abbreviations: Aib (α‐aminoisobutyric acid); Iva ( D ‐isovaline); Lx ( L ‐leucine or L ‐isoleucine); Vx ( L ‐valine or D ‐isovaline); Fol ( L ‐phenylalaninol)). Copyright © 2005 European Peptide Society and John Wiley & Sons, Ltd.