Structure of microcin J25, a peptide inhibitor of bacterial RNA polymerase, is a lassoed tail

Kelly Anne Wilson, Markus Kalkum, Jennifer Ottesen, Julia Yuzenkova, Brian T. Chait, Robert Landick, Tom Muir, Konstantin Severinov, Seth A. Darst

Research output: Contribution to journalArticlepeer-review

175 Scopus citations

Abstract

Microcin J25 (MccJ25) is a 21-amino acid peptide inhibitor active against the DNA-dependent RNA polymerase of Gram negative bacteria. Previously, the structure of MccJ25 was reported to be a head-to-tail circle, cyclo(-G 1GAGHVPEYF10VGIGTPISFY20G-). On the basis of biochemical studies, mass spectrometry, and NMR, we show that this structure is incorrect, and that the peptide has an extraordinary structural fold. MccJ25 contains an internal lactam linkage between the α-amino group of Glyl and the γ-carboxyl of Glu8. The tail (Tyr9-Gly21) passes through the ring (Gly1-Glu8), with Phe19 and Tyr20 straddling each side of the ring, sterically trapping the tail in a noncovalent interaction we call a lassoed tail.

Original languageEnglish (US)
Pages (from-to)12475-12483
Number of pages9
JournalJournal of the American Chemical Society
Volume125
Issue number41
DOIs
StatePublished - Oct 15 2003
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Catalysis
  • Chemistry(all)
  • Biochemistry
  • Colloid and Surface Chemistry

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