A systematic survey of in vivo obligate chaperonin-dependent substrates

Kei Fujiwara, Yasushi Ishihama, Kenji Nakahigashi, Tomoyoshi Soga, Hideki Taguchi

Research output: Contribution to journalArticlepeer-review

147 Citations (Scopus)


Chaperonins are absolutely required for the folding of a subset of proteins in the cell. An earlier proteome-wide analysis of Escherichia coli chaperonin GroEL/GroES (GroE) interactors predicted obligate chaperonin substrates, which were termed Class III substrates. However, the requirement of chaperonins for in vivo folding has not been fully examined. Here, we comprehensively assessed the chaperonin requirement using a conditional GroE expression strain, and concluded that only 60% of Class III substrates are bona fide obligate GroE substrates in vivo. The in vivo obligate substrates, combined with the newly identified obligate substrates, were termed Class IV substrates. Class IV substrates are restricted to proteins with molecular weights that could be encapsulated in the chaperonin cavity, are enriched in alanine/glycine residues, and have a strong structural preference for aggregation-prone folds. Notably, 70% of the Class IV substrates appear to be metabolic enzymes, supporting a hypothetical role of GroE in enzyme evolution.

Original languageEnglish
Pages (from-to)1552-1564
Number of pages13
JournalEMBO Journal
Issue number9
Publication statusPublished - 2010 May


  • Chaperonin
  • GroEL
  • Metabolomics
  • Protein folding
  • Proteomics

ASJC Scopus subject areas

  • General Neuroscience
  • Molecular Biology
  • General Biochemistry,Genetics and Molecular Biology
  • General Immunology and Microbiology


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