Escherichia coli thioredoxin-like protein YbbN contains an atypical tetratricopeptide repeat motif and is a negative regulator of GroEL

Jiusheng Lin, Mark A. Wilson

Research output: Contribution to journalArticle

4 Scopus citations


Many proteins contain a thioredoxin (Trx)-like domain fused with one or more partner domains that diversify protein function by the modular construction of new molecules. The Escherichia coli protein YbbN is a Trx-like protein that contains a C-terminal domain with low homology to tetratricopeptide repeat motifs. YbbN has been proposed to act as a chaperone or co-chaperone that aids in heat stress response and DNA synthesis. We report the crystal structure of YbbN, which is an elongated molecule with a mobile Trx domain and four atypical tetratricopeptide repeat motifs. The Trx domain lacks a canonical CXXC active site architecture and is not a functional oxidoreductase. A variety of proteins in E. coli interact with YbbN, including multiple ribosomal protein subunits and a strong interaction with GroEL. YbbN acts as a mild inhibitor of GroESL chaperonin function and ATPase activity, suggesting that it is a negative regulator of the GroESL system. Combined with previous observations that YbbN enhances the DnaK-DnaJ-GrpE chaperone system, we propose that YbbN coordinately regulates the activities of these two prokaryotic chaperones, thereby helping to direct client protein traffic initially to DnaK. Therefore, YbbN may play a role in integrating the activities of different chaperone pathways in E. coli and related bacteria.

Original languageEnglish (US)
Pages (from-to)19459-19469
Number of pages11
JournalJournal of Biological Chemistry
Issue number22
Publication statusPublished - Jun 3 2011


ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

Cite this