A substrate radical intermediate in catalysis by the antibiotic resistance protein Cfr

Tyler L. Grove, Jovan Livada, Erica L. Schwalm, Michael T. Green, Squire J. Booker, Alexey Silakov

Research output: Contribution to journalArticlepeer-review

30 Scopus citations

Abstract

Cfr-dependent methylation of C8 of A2503 in 23S ribosomal RNA confers bacterial resistance to an array of clinically important antibiotics that target the large subunit of the ribosome, including the synthetic oxazolidinone antibiotic linezolid. The key element of the proposed mechanism for Cfr, a radical S-adenosylmethionine enzyme, is the addition of a methylene radical, generated by hydrogen-atom abstraction from the methyl group of an S-methylated cysteine, onto C8 of A2503 to form a protein-nucleic acid crosslinked species containing an unpaired electron. Herein we use continuous-wave and pulsed EPR techniques to provide direct spectroscopic evidence for this intermediate, showing a spin-delocalized radical with maximum spin density at N7 of the adenine ring. In addition, we use rapid freeze-quench EPR to show that the radical forms and decays with rate constants that are consistent with the rate of formation of the methylated product

Original languageEnglish (US)
Pages (from-to)422-427
Number of pages6
JournalNature Chemical Biology
Volume9
Issue number7
DOIs
StatePublished - Jul 2013

All Science Journal Classification (ASJC) codes

  • Molecular Biology
  • Cell Biology

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