Mycoplanecins, novel antimycobacterial antibiotics from Actinoplanes awajinensis subsp. mycoplanecinus subsp. nov. III. Structural determination of mycoplanecin A.

The structure of mycoplanecin A was determined by the analysis of chemical degradation products and by mass and 1H and 13C NMR spectrometries. Mycoplanecin A is a new cyclic peptide antibiotic composed of mol each of alpha-ketobutyric acid, glycine, L-leucine, L-proline, L-2-amino-5-methylhexanoic acid, N-methyl-D-leucine, N-methyl-L-threonine, methyl-L-proline and ethyl-L-proline and two mol of N-methyl-L-valine. Among these components, ethyl-L-proline is reported for the first time as a component of natural products. A newly developed mass analysis has been introduced for the differentiation of alpha-amino acid and its N-methyl derivative.