STRUCTURE AND BIOLOGICAL FUNCTION OF PEPTIDES CONTAINING LANTHIONINE, BETA-METHYLLANTHIONINE AND ALPHA, BETA-UNSATURATED AMINO ACIDS

The polypeptide cinnamycin, from Streptomyces cinnamoneous contains unusual and crosslinking amino acids including lanthionine, (beta)-methyllanthionine, lysinoalanine and (beta)-hydroxyaspartic acid. This molecule also contains glutamic acid, glycine, proline, aspartic acid, valine, phenylalanine and arginine. The reaction of cyanogen bromide with the lysinoalanine residue in cinnamycin leads to the formation of a new amino acid which elutes in the aliphatic region of the amino acid analyzer. The aspartic and glutamic acid residues were found to be present in the amide forms and the -COOH terminus was found to be lysinoalanine by esterification and reduction. Some of the possible structures for cinnamycin are discussed. A new peptide, larger than cinnamycin was isolated and found to have an amino terminus of isoleucine (by dinitrophenylation). The synthesis of (alpha), (alpha)-diacetaminopropionic acid was successfully performed by using aqueous sulfuric acid in place of concentrated sulfuric acid. High Performance Liquid Chromatographic (HPLC) techniques for purification and analysis of cinnamycin and its degradation products have been developed. Separations of derivatized amino acids were also developed and utilized. Ion pair HPLC was used in the development of a separation of free amino acids.