Detecting Folding Intermediates of a Protein as It Passes through the Bacterial Translocation Channel

Hiroshi Kadokura, Jon Beckwith

Research output: Contribution to journalArticlepeer-review

83 Citations (Scopus)

Abstract

Most bacterial exported proteins cross the cytoplasmic membrane as unfolded polypeptides. However, little is known about how they fold during or after this process due to the difficulty in detecting folding intermediates. Here we identify cotranslational and posttranslational folding intermediates of a periplasmic protein in which the protein and DsbA, a periplasmic disulfide bond-forming enzyme, are covalently linked by a disulfide bond. The cotranslational mixed-disulfide intermediate is, upon further chain elongation, resolved, releasing the oxidized polypeptide, thus allowing us to follow the folding process. This analysis reveals that two cysteines that are joined to form a structural disulfide can play different roles during the folding reaction and that the mode of translocation (cotranslational verse posttranslational) can affect the folding process of a protein in the periplasm. The latter finding leads us to propose that the activity of the ribosome (translation) can modulate protein folding even in an extracytosolic compartment.

Original languageEnglish
Pages (from-to)1164-1173
Number of pages10
JournalCell
Volume138
Issue number6
DOIs
Publication statusPublished - 2009 Sep 18
Externally publishedYes

Keywords

  • CELLBIO
  • PROTEINS

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)

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