Molecular Dynamics Simulation Studies on the Positive Cooperativity of the Kemptide Substrate with Protein Kinase A Induced by the ATP Ligand

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• 作者：Chaoqun Li ; Na Ma ; Yaru Wang ; Yan Wang ; Guangju Chen
• 刊名：Journal of Physical Chemistry B
• 出版年：2014
• 出版时间：February 6, 2014
• 年：2014
• 卷：118
• 期：5
• 页码：1273-1287
• 全文大小：810K
• ISSN：1520-5207

文摘

The positive cooperativity of the Kemptide substrate or the ATP molecule with the PKA catalytic subunit has been studied by dynamics simulations and free energy calculations on a series of binary and ternary models. The results revealed that the first ATP binding to the PKA catalytic subunit is energetically favorable for the successive Kemptide binding, confirming the positive cooperativity. The key residues Thr51, Glu170, and Phe187 in PKA contributing to the positive cooperativity have been found. The binding of ATP to PKA induces the positive cooperativity through one direct allosteric communication network in PKA from the ATP binding sites in the catalytic loop of the large lobe to the Kemptide binding sites in the activation segment of the large lobe, two indirect ones from those in the glycine-rich loop and the 尾3 strand of the small lobe, and from those in the catalytic loop to those in the activation segment via the 伪F helix media. The Tyr204Ala mutation in the activation segment of PKA causes both the decoupling of the cooperativity and the disruption of the corresponding allosteric network through the 伪F helix media.