Effect of Cd²⁺ on muscle type of creatine kinase: Inhibition kinetics integrating computational simulations

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• 作者：Yan Cai^a ; ¹ ; Jinhyuk Lee^b ; ^c ; ¹ ; Wei Wang^a ; Jun-Mo Yang^d ; ^{junmo.yang@samsung.com" class="auth_mail" title="E-mail the corresponding author} ; Guo-Ying Qian^a ; ^{qianguoying_wanli@hotmail.com" class="auth_mail" title="E-mail the corresponding author}
• 关键词：Creatine kinase ; Cd2+ ; Inhibition
• 刊名：International Journal of Biological Macromolecules
• 出版年：2016
• 出版时间：February 2016
• 年：2016
• 卷：83
• 期：Complete
• 页码：233-241
• 全文大小：2867 K

文摘

Creatine kinase (EC 2.7.3.2, CK) plays an important role in cellular energy metabolism and homeostasis by catalyzing the transfer of phosphate between ATP and creatine phosphate. We investigated the effects of Cd²⁺ on muscle type of creatine kinase from Pelodiscus sinensis (PSCKM). Cd²⁺ conspicuously inactivated the activity of PSCKM (IC₅₀ = 0.062 mM) in a first-order kinetic process and exhibited non-competitive inhibition with creatine and ATP. A conformational study showed that Cd²⁺ induced tertiary structure changes in PSCKM with exposure of hydrophobic surfaces. The addition of osmolytes, such as glycine and proline, partially reactivated the Cd²⁺-mediated inactive PSCKM. Additionally, molecular dynamics and docking simulations between PSCKM and Cd²⁺ were conducted to show that Cd²⁺ blocked the entrance of ATP to the active site, and this result is consistent with the experimental results showing Cd²⁺-induced inactivation of PSCKM. Our study demonstrates the effect of Cd²⁺ on PSCKM enzymatic function and unfolding, including the protective effects of osmolytes on PSCKM inactivation. This study provides important insights into the changes in the PSCKM metabolic enzyme of ectothermic animals in response to the environment.