کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
2039287 | 1073043 | 2016 | 11 صفحه PDF | دانلود رایگان |
• Recoverin binds rhodopsin kinase by conformational selection
• NMR and stopped flow kinetics reveal binding mechanism
• Direct experimental distinction between conformational selection versus induced fit
• Binding-competent state with exposed hydrophobic binding pocket is only 3% populated
SummaryMolecular recognition plays a central role in biology, and protein dynamics has been acknowledged to be important in this process. However, it is highly debated whether conformational changes happen before ligand binding to produce a binding-competent state (conformational selection) or are caused in response to ligand binding (induced fit). Proposals for both mechanisms in protein/protein recognition have been primarily based on structural arguments. However, the distinction between them is a question of the probabilities of going via these two opposing pathways. Here, we present a direct demonstration of exclusive conformational selection in protein/protein recognition by measuring the flux for rhodopsin kinase binding to its regulator recoverin, an important molecular recognition in the vision system. Using nuclear magnetic resonance (NMR) spectroscopy, stopped-flow kinetics, and isothermal titration calorimetry, we show that recoverin populates a minor conformation in solution that exposes a hydrophobic binding pocket responsible for binding rhodopsin kinase. Protein dynamics in free recoverin limits the overall rate of binding.
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Journal: - Volume 14, Issue 1, 5 January 2016, Pages 32–42