Self-sacrifice in radical S-adenosylmethionine proteins

Curr Opin Chem Biol. 2007 Oct;11(5):543-52. doi: 10.1016/j.cbpa.2007.08.028.


The radical SAM superfamily of metalloproteins catalyze the reductive cleavage of S-adenosyl-l-methionine to generate a 5'-deoxyadenosyl radical (5'-dA*) intermediate that is obligate for turnover. The 5'-dA* acts as a potent oxidant, initiating turnover by abstracting a hydrogen atom from an appropriate substrate. A special class of these enzymes use this strategy to functionalize unactivated C-H bonds by insertion of sulfur atoms. This review will describe the characterization of three members of this class - biotin synthase, lipoyl synthase, and MiaB protein - each of which has been shown to cannibalize itself during turnover.

Publication types

  • Research Support, N.I.H., Extramural
  • Review

MeSH terms

  • Escherichia coli Proteins / metabolism
  • Free Radicals
  • Hydrogenation
  • Proteins / metabolism*
  • S-Adenosylmethionine / metabolism*
  • Sulfurtransferases / metabolism


  • Escherichia coli Proteins
  • Free Radicals
  • Proteins
  • S-Adenosylmethionine
  • MiaB protein, E coli
  • Sulfurtransferases
  • biotin synthetase