Global aggregation of newly translated proteins in an Escherichia coli strain deficient of the chaperonin GroEL

Eli Chapman, George W. Farr, Renata Usaite, Krystyna Furtak, Wayne A. Fenton, Tapan K. Chaudhuri, Elise R. Hondorp, Rowena G. Matthews, Sharon G. Wolf, John R. Yates, Marc Pypaert, Arthur L. Horwich

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121 Scopus citations


In a newly isolated temperature-sensitive lethal Escherichia coli mutant affecting the chaperonin GroEL, we observed wholesale aggregation of newly translated proteins. After temperature shift, transcription, translation, and growth slowed over two to three generations, accompanied by filamentation and accretion (in ≈2% of cells) of paracrystalline arrays containing mutant chaperonin complex. A biochemically isolated inclusion body fraction contained the collective of abundant proteins of the bacterial cytoplasm as determined by SDS/PAGE and proteolysis/MS analyses. Pulse-chase experiments revealed that newly made proteins, but not preexistent ones, were recruited to this insoluble fraction. Although aggregation of "stringent" GroEL/GroES-dependent substrates may secondarily produce an "avalanche" of aggregation, the observations raise the possibility, supported by in vitro refolding experiments, that the widespread aggregation reflects that GroEL function supports the proper folding of a majority of newly translated polypeptides, not just the limited number indicated by interaction studies and in vitro experiments.

Original languageEnglish (US)
Pages (from-to)15800-15805
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number43
StatePublished - Oct 24 2006


  • Chaperone
  • Misfolding
  • Protein folding

ASJC Scopus subject areas

  • General


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