Identification of nascent chain interaction sites on trigger factor

Sathish K. Lakshmipathy, Sladjana Tomic, Christian M. Kaiser, Hung Chun Chang, Pierre Genevaux, Costa Georgopoulos, José M. Barral, Arthur E. Johnson, F. Ulrich Hartl, Stephanie A. Etchells

Research output: Contribution to journalArticlepeer-review

59 Scopus citations

Abstract

The role of ribosome-binding molecular chaperones in protein folding is not yet well understood. Trigger factor (TF) is the first chaperone to interact with nascent polypeptides as they emerge from the bacterial ribosome. It binds to the ribosome as a monomer but forms dimers in free solution. Based on recent crystal structures, TF has an elongated shape, with the peptidylprolyl-cis/ trans-isomerase (PPIase) domain and the N-terminal ribosome binding domain positioned at opposite ends of the molecule and the C-terminal domain, which forms two arms, positioned in between. By using site specifically labeled TF proteins, we have demonstrated that all three domains of TF interact with nascent chains during translation. Interactions with the PPIase domain were length-dependent but independent of PPIase activity. Interestingly, with free TF, these same sites were found to be involved in forming the dimer interface, suggesting that dimerization partially occludes TF-nascent chain binding sites. Our data indicate the existence of two regions on TF along which nascent chains can interact, the NC-domains as the main site and the PPIase domain as an auxiliary site.

Original languageEnglish (US)
Pages (from-to)12186-12193
Number of pages8
JournalJournal of Biological Chemistry
Volume282
Issue number16
DOIs
StatePublished - Apr 20 2007
Externally publishedYes

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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