Structure of subtilosin A, an antimicrobial peptide from Bacillus subtilis with unusual posttranslational modifications linking cysteine sulfurs to alpha-carbons of phenylalanine and threonine

J Am Chem Soc. 2003 Apr 23;125(16):4726-7. doi: 10.1021/ja029654t.

Abstract

The complete primary and three-dimensional solution structures of subtilosin A (1), a bacteriocin from Bacillus subtilis, were determined by multidimensional NMR studies on peptide produced using isotopically labeled [(13)C,(15)N]medium derived from Anabaena sp. grown on sodium [(13)C]bicarbonate and [(15)N]nitrate. Additional samples of 1 were also generated by separate incorporations of [U-(13)C,(15)N]phenylalanine and [U-(13)C,(15)N]threonine using otherwise unlabeled media. The results demonstrate that in addition to having a cyclized peptide backbone (N and C termini), three cross-links are formed between the sulfurs of Cys13, Cys7, and Cys4 and the alpha-positions of Phe22, Thr28, and Phe31, respectively. Such posttranslational linkage of a thiol to the alpha-carbon of an amino acid residue is very unusual in natural peptides or proteins. Subtilosin A (1) belongs to a new class of bacteriocins.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Anti-Bacterial Agents / chemistry
  • Anti-Bacterial Agents / metabolism*
  • Bacillus subtilis / metabolism*
  • Bacterial Proteins*
  • Bacteriocins
  • Cysteine / metabolism*
  • Models, Molecular
  • Molecular Sequence Data
  • Nuclear Magnetic Resonance, Biomolecular
  • Peptides*
  • Peptides, Cyclic
  • Phenylalanine / metabolism
  • Protein Conformation
  • Protein Processing, Post-Translational*
  • Threonine / metabolism

Substances

  • Anti-Bacterial Agents
  • Bacterial Proteins
  • Bacteriocins
  • Peptides
  • Peptides, Cyclic
  • Threonine
  • Phenylalanine
  • sboA protein, Bacillus subtilis
  • Cysteine