The structure of permetin A, a new polypeptin type antibiotic produced by Bacillus circulans

The structure of permetin A(I), an antibiotic substance produced by Bacillus circulans AJ 3902, has been elucidated as a cyclic acyl peptide by means of the mass and nuclear magnetic resonance spectroscopic techniques. (Formula: see text.) The structure was found to be the same as polypeptin A(II) except that L-Thr in II is replaced by L-Ser in I. Details of the structural determination are given for the permetin A itself as well as for the hydrolyzed permetin A. (Formula: see text.)