The Library
Alternative conformations of the x region of human protein disulphide-isomerase modulate exposure of the substrate binding b’ domain
Tools
Dat Nguyen, Van, Wallis, A. Katrine, Howard, Mark J., Haapalainen, Antti M., Salo, Kirsi E. H., Saaranen, Mirva J. , Sidhu, Ateesh, Wierenga, Rik K., Freedman, R. B., Ruddock, Lloyd W. and Williamson, Richard A. (2008) Alternative conformations of the x region of human protein disulphide-isomerase modulate exposure of the substrate binding b’ domain. Journal of Molecular Biology, Vol.383 (No.5). pp. 1144-1155. doi:10.1016/j.jmb.2008.08.085 ISSN 0022-2836.
|
PDF
WRAP_Wallis_0380075-211108-sdarticle.pdf - Requires a PDF viewer. Download (755Kb) |
Official URL: http://dx.doi.org/10.1016/j.jmb.2008.08.085
Abstract
Protein disulphide isomerase (PDI) is a key multi-domain protein folding catalyst in the endoplasmic reticulum. The b’ domain of PDI is essential for the non-covalent binding of incompletely folded protein substrates. Earlier, we defined the substrate binding site in the b’ domain of human PDI by modelling and mutagenesis studies. Here, we show by fluorescence and NMR that recombinant human PDI b’x (comprising the b’ domain and the subsequent x linker region) can assume at least two different conformations in solution. We have screened mutants in the b’x region to identify mutations that favour one of these conformers in recombinant b'x, and isolated and characterised examples of both types. We have crystallised one mutant of b’x (I272A mutation) in which one conformer is stabilized, and determined its crystal structure to a resolution of 2.2 Å. This structure shows that the b’ domain has the typical thioredoxin fold and that the x region can interact with the b’ domain by ”capping” a hydrophobic site on the b’ domain. This site is most likely the substrate binding site and hence such capping will inhibit substrate binding. All of the mutations we previously reported to inhibit substrate binding shift the equilibrium towards the capped conformer. Hence, these mutations act by altering the natural equilibrium and decreasing the accessibility of the substrate binding site. Furthermore, we have confirmed that the corresponding structural transition occurs in the wild type full-length PDI. A cross-comparison of our data with that for other PDI-family members, Pdi1p and ERp44, suggests that the x region of PDI can adopt alternative conformations during the functional cycle of PDI action and that these are linked to the ability of PDI to interact with folding substrates.
Item Type: | Journal Article | ||||
---|---|---|---|---|---|
Subjects: | R Medicine > R Medicine (General) | ||||
Divisions: | Faculty of Science, Engineering and Medicine > Science > Life Sciences (2010- ) > Biological Sciences ( -2010) | ||||
Library of Congress Subject Headings (LCSH): | Protein disulphide isomerase | ||||
Journal or Publication Title: | Journal of Molecular Biology | ||||
Publisher: | Academic Press | ||||
ISSN: | 0022-2836 | ||||
Official Date: | 9 September 2008 | ||||
Dates: |
|
||||
Volume: | Vol.383 | ||||
Number: | No.5 | ||||
Page Range: | pp. 1144-1155 | ||||
DOI: | 10.1016/j.jmb.2008.08.085 | ||||
Status: | Peer Reviewed | ||||
Access rights to Published version: | Open Access (Creative Commons) | ||||
Funder: | Biotechnology and Biological Sciences Research Council (Great Britain) (BBSRC), Suomen Akatemia [Academy of Finland], Sigrid Jusélius stiftelse, Biocenter Oulu, Oulun yliopisto [University of Oulu], University of Warwick | ||||
Grant number: | Grant BB/D017807 (BBSRC) |
Data sourced from Thomson Reuters' Web of Knowledge
Request changes or add full text files to a record
Repository staff actions (login required)
View Item |
Downloads
Downloads per month over past year