Structure of antibacterial peptide microcin J25: A 21-residue lariat protoknot

Marvin J. Bayro, Jayanta Mukhopadhyay, G. V.T. Swapna, Janet Y. Huang, Li Chung Ma, Elena Sineva, Philip E. Dawson, Gaetano T. Montelione, Richard H. Ebright

Research output: Contribution to journalArticlepeer-review

185 Scopus citations


The antibacterial peptide microcin J25 (MccJ25) inhibits bacterial transcription by binding within, and obstructing, the nucleotide-uptake channel of bacterial RNA polymerase. Published covalent and three-dimensional structures indicate that MccJ25 is a 21-residue cycle. Here, we show that the published covalent and three-dimensional structures are incorrect, and that MccJ25 in fact is a 21-residue "lariat protoknot", consisting of an 8-residue cyclic segment followed by a 13-residue linear segment that loops back and threads through the cyclic segment. MccJ25 is the first example of a lariat protoknot involving a backbone-side chain amide linkage.

Original languageEnglish (US)
Pages (from-to)12382-12383
Number of pages2
JournalJournal of the American Chemical Society
Issue number41
StatePublished - Oct 15 2003

All Science Journal Classification (ASJC) codes

  • Catalysis
  • General Chemistry
  • Biochemistry
  • Colloid and Surface Chemistry


Dive into the research topics of 'Structure of antibacterial peptide microcin J25: A 21-residue lariat protoknot'. Together they form a unique fingerprint.

Cite this