Deciphering Nature's Intricate Way of N,S-Dimethylating l-Cysteine: Sequential Action of Two Bifunctional Adenylation Domains

Biochemistry. 2017 Nov 21;56(46):6087-6097. doi: 10.1021/acs.biochem.7b00980. Epub 2017 Nov 7.


Dimethylation of amino acids consists of an interesting and puzzling series of events that could be achieved, during nonribosomal peptide biosynthesis, either by a single adenylation (A) domain interrupted by a methyltransferase (M) domain or by the sequential action of two of such independent enzymes. Herein, to establish the method by which Nature N,S-dimethylates l-Cys, we studied its formation during thiochondrilline A biosynthesis by evaluating TioS(A3aM3SA3bT3) and TioN(AaMNAb). This study not only led to identification of the exact pathway followed in Nature by these two enzymes for N,S-dimethylation of l-Cys, but also revealed that a single interrupted A domain can N,N-dimethylate amino acids, a novel phenomenon in the nonribosomal peptide field. These findings offer important and useful insights for the development and engineering of novel interrupted A domain enzymes to serve, in the future, as tools for combinatorial biosynthesis.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Biosynthetic Pathways
  • Cysteine / metabolism*
  • Hydroxyquinolines / metabolism*
  • Methylation
  • Micromonosporaceae / enzymology*
  • Micromonosporaceae / metabolism*
  • Oligopeptides / metabolism*
  • Peptide Biosynthesis, Nucleic Acid-Independent
  • Peptide Synthases / chemistry
  • Peptide Synthases / metabolism*
  • Protein Domains


  • Hydroxyquinolines
  • Oligopeptides
  • Peptide Synthases
  • non-ribosomal peptide synthase
  • Cysteine