[HTML][HTML] Protein folding drives disulfide formation

P Kosuri, J Alegre-Cebollada, J Feng, A Kaplan… - Cell, 2012 - cell.com
P Kosuri, J Alegre-Cebollada, J Feng, A Kaplan, A Inglés-Prieto, CL Badilla, BR Stockwell
Cell, 2012cell.com
PDI catalyzes the oxidative folding of disulfide-containing proteins. However, the sequence
of reactions leading to a natively folded and oxidized protein remains unknown. Here we
demonstrate a technique that enables independent measurements of disulfide formation
and protein folding. We find that non-native disulfides are formed early in the folding
pathway and can trigger misfolding. In contrast, a PDI domain favors native disulfides by
catalyzing oxidation at a late stage of folding. We propose a model for cotranslational …
Summary
PDI catalyzes the oxidative folding of disulfide-containing proteins. However, the sequence of reactions leading to a natively folded and oxidized protein remains unknown. Here we demonstrate a technique that enables independent measurements of disulfide formation and protein folding. We find that non-native disulfides are formed early in the folding pathway and can trigger misfolding. In contrast, a PDI domain favors native disulfides by catalyzing oxidation at a late stage of folding. We propose a model for cotranslational oxidative folding wherein PDI acts as a placeholder that is relieved by the pairing of cysteines caused by substrate folding. This general mechanism can explain how PDI catalyzes oxidative folding in a variety of structurally unrelated substrates.
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