Catalysis of creatine kinase refolding by protein disulfide isomerase involves disulfide cross-link and dimer to tetramer switch

Tong Jin Zhao, Wen Bin Ou, Qiang Xie, Yang Liu, Yong Bin Yan, Hai Meng Zhou

Research output: Contribution to journalArticlepeer-review

42 Scopus citations

Abstract

Protein disulfide isomerase (PDI) functions as an isomerase to catalyze thiol:disulfide exchange, as a chaperone to assist protein folding, and as a subunit of prolyl-4-hydroxylase and microsomal triglyceride transfer protein. At a lower concentration of 0.2 μM, PDI facilitated the aggregation of unfolded rabbit muscle creatine kinase (CK) and exhibited anti-chaperone activity, which was shown to be mainly due to the hydrophobic interactions between PDI and CK and was independent of the cross-linking of disulfide bonds. At concentrations above 1 μM, PDI acted as a protector against aggregation but an inhibitor of reactivation during CK refolding. The inhibition effect of PDI on CK reactivation was further characterized as due to the formation of PDI-CK complexes through intermolecular disulfide bonds, a process involving Cys-36 and Cys-295 of PDI. Two disulfide-linked complexes containing both PDI and CK were obtained, and the large, soluble aggregates around 400 kDa were composed of 1 molecule of tetrameric PDI and 2 molecules of inactive intermediate dimeric CK, whereas the smaller one, around 200 kDa, was formed by 1 dimeric PDI and 1 dimeric CK. To our knowledge this is the first study revealing that PDI could switch its conformation from dimer to tetramer in its functions as a foldase. According to the observations in this research and our previous study of the folding pathways of CK, a working model was proposed for the molecular mechanism of CK refolding catalyzed by PDI.

Original languageEnglish (US)
Pages (from-to)13470-13476
Number of pages7
JournalJournal of Biological Chemistry
Volume280
Issue number14
DOIs
StatePublished - Apr 8 2005

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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