Download MendeleyThioredoxin fold as homodimerization module in the putative chaperone ERp29: NMR structures of the domains and experimental model of the 51 kDa dimer.
Liepinsh, E., Baryshev, M., Sharipo, A., Ingelman-Sundberg, M., Otting, G., Mkrtchian, S.(2001) Structure 9: 457-471
- PubMed: 11435111
- DOI: https://doi.org/10.1016/s0969-2126(01)00607-4
- Primary Citation of Related Structures:
1G7D, 1G7E - PubMed Abstract:
ERp29 is a ubiquitously expressed rat endoplasmic reticulum (ER) protein conserved in mammalian species. Fold predictions suggest the presence of a thioredoxin-like domain homologous to the a domain of human protein disulfide isomerase (PDI) and a helical domain similar to the C-terminal domain of P5-like PDIs. As ERp29 lacks the double-cysteine motif essential for PDI redox activity, it is suggested to play a role in protein maturation and/or secretion related to the chaperone function of PDI. ERp29 self-associates into 51 kDa dimers and also higher oligomers. 3D structures of the N- and C-terminal domains determined by NMR spectroscopy confirmed the thioredoxin fold for the N-terminal domain and yielded a novel all-helical fold for the C-terminal domain. Studies of the full-length protein revealed a short, flexible linker between the two domains, homodimerization by the N-terminal domain, and the presence of interaction sites for the formation of higher molecular weight oligomers. A gadolinium-based relaxation agent is shown to present a sensitive tool for the identification of macromolecular interfaces by NMR. ERp29 is the first eukaryotic PDI-related protein for which the structures of all domains have been determined. Furthermore, an experimental model of the full-length protein and its association states was established. It is the first example of a protein where the thioredoxin fold was found to act as a specific homodimerization module, without covalent linkages or supporting interactions by further domains. A homodimerization module similar as in ERp29 may also be present in homodimeric human PDI.
Organizational Affiliation:
Department of Medical Biochemistry and Biophysics, Karolinska Institute, 171 77, Stockholm, Sweden.
