A substrate-driven allosteric switch that enhances PDI catalytic activity

Journal Article · Tue Aug 30 00:00:00 EDT 2016 · Nature Communications

DOI:https://doi.org/10.1038/ncomms12579· OSTI ID:1623845

Bekendam, Roelof H. ^[1]; Bendapudi, Pavan K. ^[2]; Lin, Lin ^[2]; Nag, Partha P. ^[3]; Pu, Jun ^[4]; Kennedy, Daniel R. ^[5]; Feldenzer, Alexandra ^[5]; Chiu, Joyce ^[6]; Cook, Kristina M. ^[7]; Furie, Bruce ^[2]; Huang, Mingdong ^[2]; Hogg, Philip J. ^[8]; Flaumenhaft, Robert ^[2]

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1. Harvard Medical School, Boston, MA (United States). Div. of Hemostasis and Thrombosis, Dept. of Medicine, Beth Israel Deaconess Medical Center; DOE/OSTI
2. Harvard Medical School, Boston, MA (United States). Div. of Hemostasis and Thrombosis, Dept. of Medicine, Beth Israel Deaconess Medical Center
3. The Broad Institute Probe Development Center, Cambridge, MA (United States). Department of Pharmaceutical and Administrative Sciences; Center for the Science of Therapeutics, Broad Institute, Cambridge, MA (United States)
4. The Broad Institute Probe Development Center, Cambridge, MA (United States). Dept. of Pharmaceutical and Administrative Sciences
5. Western New England Univ., Springfield, MA (United States). College of Pharmacy
6. The Centenary Institute, Newtown, Sydney, New South Wales, Australia; National Health and Medical Research Council Clinical Trials Centre, University of Sydney, Sydney, New South Wales, Australia
7. The Centenary Institute, Newtown, Sydney, New South Wales, Australia
8. The Centenary Institute, Newtown, 2050, Sydney, New South Wales, Australia; National Health and Medical Research Council Clinical Trials Centre, University of Sydney, Sydney, 2050, New South Wales, Australia

Protein disulfide isomerase (PDI) is an oxidoreductase essential for folding proteins in the endoplasmic reticulum. The domain structure of PDI is a–b–b'–x–a', wherein the thioredoxin-like a and a' domains mediate disulfide bond shuffling and b and b' domains are substrate binding. The b' and a' domains are connected via the x-linker, a 19-amino-acid flexible peptide. Here we identify a class of compounds, termed bepristats, that target the substrate-binding pocket of b'. Bepristats reversibly block substrate binding and inhibit platelet aggregation and thrombus formation in vivo. Ligation of the substrate-binding pocket by bepristats paradoxically enhances catalytic activity of a and a' by displacing the x-linker, which acts as an allosteric switch to augment reductase activity in the catalytic domains. This substrate-driven allosteric switch is also activated by peptides and proteins and is present in other thiol isomerases. Our results demonstrate a mechanism whereby binding of a substrate to thiol isomerases enhances catalytic activity of remote domains.

• Research Organization: Lawrence Berkeley National Lab (LBNL), Berkeley, CA (United States)
• Sponsoring Organization: Hemostasis and Thrombosis Research Society; NIH Molecular Libraries Probe Production Centers Network (MLPCN); National Institute on Drug Abuse (NIDA); National Institutes of Health (NIH) National Heart, Lung, and Blood Institute (NHLBI); USDOE Office of Science (SC)
• Grant/Contract Number: AC02-05CH11231
• OSTI ID: 1623845
• Journal Information: Nature Communications, Journal Name: Nature Communications Journal Issue: 1 Vol. 7; ISSN 2041-1723
• Publisher: Nature Publishing Group
• Country of Publication: United States
• Language: English

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