Towards Binding Mechanism of Cu²⁺ on Creatine Kinase from Pelodiscus sinensis: Molecular Dynamics Simulation Integrating Inhibition Kinetics Study

Title:Towards Binding Mechanism of Cu²⁺ on Creatine Kinase from Pelodiscus sinensis: Molecular Dynamics Simulation Integrating Inhibition Kinetics Study

Volume: 24 Issue: 6

Author(s): Yan Cai, Jinhyuk Lee, Wei Wang, Yong-Doo Park*Guo-Ying Qian*

Affiliation:

• College of Biological and Environmental Sciences, Zhejiang Wanli University, Ningbo 315100,China

• College of Biological and Environmental Sciences, Zhejiang Wanli University, Ningbo 315100,China

Keywords: Creatine kinase, Pelodiscus sinensis, Cu²⁺, MD simulation, inactivation, osmolytes.

Abstract: Background: Cu²⁺ is well known to play important roles in living organisms having bifacial distinction: essential microelement that is necessary for a wide range of metabolic processes but hyper-accumulation of Cu²⁺ can be toxic. The physiological function of Cu²⁺ in ectothermic animals such as Pelodiscus sinensis (Chinese soft-shelled turtle) has not been elucidated.

Objective: In this study, we elucidated effect of Cu²⁺ on the energy producing metabolic enzyme creatine kinase (CK), which might directly affect energy metabolism and homeostasis of P. sinensis.

Method: We first conducted molecular dynamics (MD) simulations between P-CK and Cu²⁺ and conducted the inactivation kinetics including spectrofluorimetry study.

Results: MD simulation showed that Cu²⁺blocked the binding site of the ATP cofactor, indicating that Cu²⁺ could directly inactivate P-CK. We prepared the muscle type of CK (P-CK) and confirmed that Cu²⁺ conspicuously inactivated the activity of P-CK (IC₅₀ = 24.3 μM) and exhibited non-competitive inhibition manner with creatine and ATP in a first-order kinetic process. This result was well matched to the MD simulation results that Cu²⁺-induced non-competitive inactivation of P-CK. The spectrofluorimetry study revealed that Cu²⁺ induced tertiary structure changes in PCK accompanying with the exposure of hydrophobic surfaces. Interestingly, the addition of osmolytes (glycine, proline, and liquaemin) effectively restored activity of the Cu²⁺-inactivated P-CK.

Conclusion: Our study illustrates the Cu²⁺-mediated unfolding of P-CK with disruption of the enzymatic function and the protective restoration role of osmolytes on P-CK inactivation. This study provides information of interest on P-CK as a metabolic enzyme of ectothermic animal in response to Cu²⁺ binding.

Cite this article as:

Cai Yan, Lee Jinhyuk, Wang Wei, Park Yong-Doo*, Qian Guo-Ying*, Towards Binding Mechanism of Cu²⁺ on Creatine Kinase from Pelodiscus sinensis: Molecular Dynamics Simulation Integrating Inhibition Kinetics Study, Protein & Peptide Letters 2017; 24 (6) . https://dx.doi.org/10.2174/0929866524666170227122706

DOI https://dx.doi.org/10.2174/0929866524666170227122706	Print ISSN 0929-8665
Publisher Name Bentham Science Publisher	Online ISSN 1875-5305