Conversion of a chaperonin GroEL-independent protein into an obligate substrate

Takuya Ishimoto, Kei Fujiwara, Tatsuya Niwa, Hideki Taguchi

Research output: Contribution to journalArticlepeer-review

13 Citations (Scopus)


Chaperones assist protein folding by preventing unproductive protein aggregation in the cell. In Escherichia coli, chaperonin GroEL/GroES (GroE) is the only indispensable chaperone and is absolutely required for the de novo folding of at least ∼60 proteins. We previously found that several orthologs of the obligate GroE substrates in Ureaplasma urealyticum, which lacks the groE gene in the genome, are E. coli GroE-independent folders, despite their significant sequence identities. Here, we investigated the key features that define the GroE dependence. Chimera or random mutagenesis analyses revealed that independent multiple point mutations, and even single mutations, were sufficient to confer GroE dependence on the Ureaplasma MetK. Strikingly, the GroE dependence was well correlated with the propensity to form protein aggregates during folding. The results reveal the delicate balance between GroE dependence and independence. The function of GroE to buffering the aggregation-prone mutations plays a role in maintaining higher genetic diversity of proteins.

Original languageEnglish
Pages (from-to)32073-32080
Number of pages8
JournalJournal of Biological Chemistry
Issue number46
Publication statusPublished - 2014 Nov 14

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology


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