白藜芦醇与CopC的相互作用研究

Study on Hydrophobic Interaction of Resveratrol with CopC by Spectroscopic and Docking Methods

白藜芦醇是一种天然的植物抗毒素,存在于花生、葡萄和多种浆果之中。CopC是一种由β-折叠片组成的铜伴侣蛋白,含有102个氨基酸,Cu^(+)结合在C端,Cu^(2+)结合在N端,其作为氧化还原开关参与铜的调控,它与小分子的作用影响其氧化还原开关功能。本研究主要利用红外光谱(FTIR)、圆二色谱(CD)、荧光寿命、三维荧光光谱、荧光光谱和分子对接等方法研究白藜芦醇与CopC的相互作用。通过FTIR、CD、化学变性和荧光寿命测定表明,白藜芦醇的结合使得CopC的稳定性降低,可能源于CopC的β-折叠片含量减少,自由卷曲含量增加。此外,三维荧光光谱和荧光光谱表明,白藜芦醇与CopC结合后,其荧光光谱出现蓝移,表明白藜芦醇可能结合在CopC的疏水区域;并且,可得白藜芦醇与CopC的结合比为1∶1,结合常数为(6.76±0.17)×10^(5) L·mol^(-1),疏水作用力是维持两者之间形成复合物的主要作用力。通过F9rster能量转移和分子对接模拟确定CopC中白藜芦醇和色氨酸之间的平均结合距离,模拟的结果和实验结果具有较好的一致性。本文结果将为阐明CopC的铜调控机理提供帮助。

Resveratrol,a natural phytoalexin as well as a type of polyphenolic compound,exists in peanuts,wines,grapes and different berries.CopC is a redox switch for modulating copper,and its interaction with small molecules affects the switching function.This work focuses on investigating the resveratrol-CopC interaction using FTIR,CD,fluorescence lifetime,three-dimensional(3 D)fluorescence spectroscopy,fluorescence spectroscopic and molecular docking.As revealed by the FTIR,CD and fluorescence lifetime assays,the combination of resveratrol changed the conformation of CopC.The results suggested that the content ofβ-sheet decreased,and the content of random coil increased.The 3 D fluorescence spectroscopy and molecular docking studies showed that after resveratrol is combined with CopC,the fluorescence spectrum appears blue shift,indicating that resveratrol may be bound to the hydrophobic region of CopC.Also,as demonstrated by the fluorescence quenching data,resveratrol and CopC present a binding ratio of 1∶1,and the obtained binding constant is(6.76±0.17)×10^(5) L·mol^(-1).Based on thermodynamic parameters,CopC-resveratrol complex is formed under the impact of hydrophobic force.What’s more,F9 rster non-radioactive resonance energy transfer together with molecular docking were used to determine the average binding distance between the resveratrol and the tryptophan in CopC.The simulation results are in good agreement with the experimental results.This study will provide help to clarify the copper regulation mechanism of CopC.