The ligand-binding b' domain of human protein disulphide-isomerase mediates homodimerization

Wallis, Anne Katrine and Sidhu, Ateesh and Byrne, Lee J. and Howard, Mark J. and Ruddock, Lloyd W. and Williamson, Richard A. and Freedman, Robert B. (2009) The ligand-binding b' domain of human protein disulphide-isomerase mediates homodimerization. Protein Science, 18 (12). pp. 2569-2577. ISSN 0961-8368. (The full text of this publication is not currently available from this repository. You may be able to access a copy if URLs are provided)

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Purified preparations of the recombinant b'x domain fragment of human protein-disulphide isomerase (PDI), which are homogeneous by mass spectrometry and sodium dodecyl sulfate polyacrylamide gel electrophoresis, comprise more than one species when analyzed by ion-exchange chromatography and nondenaturing polyacrylamide gel electrophoresis. These species were resolved and shown to be monomer and dimer by analytical ultracentrifugation and analytical size-exclusion chromatography. Spectroscopic properties indicate that the monomeric species corresponds to the "capped" conformation observed in the x-ray structure of the I272A mutant of b'x (Nguyen, Wallis, Howard, Haapalainen, Salo, Saaranen, Sidhu, Wierenga, Freedman, Ruddock, and Williamson, J Mol Biol 2008;383:1144-1155) in which the x region binds to a hydrophobic patch on the surface of the b' domain; conversely, the dimeric species has an "open" or "uncapped" conformation in which the x region does not bind to this surface. The larger bb'x fragment of human PDI shows very similar behavior to b'x and can be resolved into a capped monomeric species and an uncapped dimer. Preparations of recombinant b' domain of human PDI and of the bb' domain pair are found exclusively as dimers. Full-length PDI is known to comprise a mixture of monomeric and dimeric species, whereas the isolated a, b, and a' domains of PDI are found exclusively as monomers. These results show that the b' domain of human PDI tends to form homodimers--both in isolation and in other contexts--and that this tendency is moderated by the adjacent x region, which can bind to a surface patch on the b' domain.

Item Type: Article
Additional information: Wallis, Anne Katrine Sidhu, Ateesh Byrne, Lee J Howard, Mark J Ruddock, Lloyd W Williamson, Richard A Freedman, Robert B BB/D017807/Biotechnology and Biological Sciences Research Council/United Kingdom Research Support, Non-U.S. Gov't United States Protein science : a publication of the Protein Society Protein Sci. 2009 Dec;18(12):2569-77.
Uncontrolled keywords: Humans Ligands Protein Disulfide-Isomerases/*chemistry Protein Multimerization Protein Structure, Tertiary
Subjects: Q Science > QD Chemistry
Q Science > QH Natural history > QH301 Biology
Divisions: Faculties > Science Technology and Medical Studies > School of Biosciences > Protein Science Group
Depositing User: Mark Howard
Date Deposited: 16 Aug 2011 03:49
Last Modified: 07 May 2014 13:25
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