PLIPASTATINS: NEW INHIBITORS OF PHOSPHOLIPASE A₂, PRODUCED BY BACILLUS CEREUS BMG302-fF67

II. STRUCTURE OF FATTY ACID RESIDUE AND AMINO ACID SEQUENCE

Abstract

Plipastatins, new inhibitors of phospholipase A₂, were produced by a strain classified as Bacillus cereus BMG302-fF67. The plipastatins are a family of acylated decapeptides which differ from each other by amino acid composition and the nature of the fatty acid side chain. The fatty acids have been shown to be 3(R)-hydroxyhexadecanoic acid (n-C₁₆h³) and 14(S)-methyl-3(R)-hydroxyhexadecanoic acid (a-C₁₆h³) by mass, NMR and optical rotation. Amino acid sequence analysis by secondary ion mass spectrometry and additional physico-chemical evidence indicate that the structures of plipastatinic acids, the lactone-opened peptides are as follows:β-Hydroxy fatty acid→L→Glu→D-Orn→L→Tyr→D-allo→Thr→L-Glu→D-Ala(Val)→L-Pro→L-Gln→D-Tyr→L-Ile-OH.