College of Biological and Environmental Sciences, Zhejiang Wanli University, Ningbo 315100, PR China.
Korean Bioinformation Center (KOBIC), Korea Research Institute of Bioscience and Biotechnology, Daejeon 305-806, Republic of Korea; Department of Nanobiotechnology and Bioinformatics, University of Sciences and Technology, Daejeon 305-350, Republic of Korea.
Int J Biol Macromol. 2017 Dec;105(Pt 3):1595-1601. doi: 10.1016/j.ijbiomac.2017.03.025. Epub 2017 Mar 7.
Creatine kinase (EC 2.7.3.2, CK) plays an important role in cellular energy metabolism and homeostasis by catalysing the transfer of phosphate between ATP and creatine phosphate. In this study, we investigated the effects of HO on PSCKM (muscle type creatine kinase from Pelodiscus sinensis) by the integrating method between enzyme kinetics and docking simulations. We found that HO strongly inactivated PSCKM (IC=0.25mM) in a first-order kinetic process, and targeted the active site cysteine directly. A conformational study showed that HO did not induce the tertiary structural changes in PSCKM with no extensive exposure of hydrophobic surfaces. Sequential docking simulations between PSCKM and HO indicated that HO interacts with the ADP binding region of the active site, consistent with experimental results that demonstrated HO-induced inactivation. Our study demonstrates the effect of HO on PSCKM enzymatic function and unfolding, and provides important insight into the changes undergone by this central metabolic enzyme in ectothermic animals in response to the environment.
肌酸激酶（EC 2.7.3.2，CK）通过催化 ATP 和磷酸肌酸之间的磷酸转移，在细胞能量代谢和稳态中发挥重要作用。在这项研究中，我们通过酶动力学和对接模拟相结合的方法，研究了 HO 对 PSCKM（中华鳖肌肉型肌酸激酶）的影响。我们发现 HO 以一级动力学过程强烈地使 PSCKM 失活（IC=0.25mM），并直接靶向活性位点半胱氨酸。构象研究表明，HO 不会引起 PSCKM 的三级结构变化，也不会暴露出广泛的疏水性表面。PSCKM 和 HO 之间的连续对接模拟表明，HO 与活性位点的 ADP 结合区域相互作用，与实验结果一致，表明 HO 诱导失活。我们的研究表明 HO 对 PSCKM 酶功能和展开的影响，并为变温动物中这种中心代谢酶对环境的响应所经历的变化提供了重要的见解。
