Structure of subtilosin A, a cyclic antimicrobial peptide from Bacillus subtilis with unusual sulfur to alpha-carbon cross-links: formation and reduction of alpha-thio-alpha-amino acid derivatives

Multidimensional NMR studies on subtilosin A, a bacteriocin from Bacillus subtilis, are carried out to determine the complete primary and three-dimensional solution structure of peptide. Results depicted a cyclized peptide backbone with three cross-links formed between the sulfurs of Cys13, Cys 7, and Cys4 and the alpha-positions of Phe22, Thr28 and Phe31 that are showing L form of stereochemistry.