石金钱龟板来源的寡肽与环氧合酶-2 相互作用机制  

Interaction mechanism between oligopeptides from yellow pond turtle and cyclooxygenase-2 based on fluorescence spectroscopy and molecular docking

作　　者：闫佳兴 张久亮 YAN Jiaxing;ZHANG Jiuliang(College of Food Science and Technology,Huazhong Agricultural University/Key Laboratory of Environment Correlative Dietology,Ministry of Education,Wuhan 430070,China)

机构地区：[1]华中农业大学食品科学技术学院/环境食品学教育部重点实验室,武汉430070

出　　处：《华中农业大学学报》2022年第5期169-178,共10页Journal of Huazhong Agricultural University

基　　金：国家重点研发计划项目(2021YFE0194000)。

摘　　要：为探究石金钱龟板来源的寡肽KNGP能否作为COX-2(环氧合酶-2)的新型抑制剂,通过紫外分光光度法测定石金钱龟板肽YPTP、合成肽段KNGP和RG的IC_(50)值,利用内源荧光、同步荧光、三维荧光光谱和ANS(1-苯胺基-8-萘磺酸)荧光探针法分析KNGP对COX-2的疏水性影响,利用分子对接方法分析KNGP与COX-2间的相互作用方式。结果显示,YPTP、KNGP和RG的IC_(50)值分别为0.609、0.046和0.056 mg/mL,KNGP的IC_(50)值低于阳性药布洛芬(IC_(50)=0.217 mg/mL),说明KNGP对COX-2具有显著的抑制潜力。内源荧光结果显示KNGP对COX-2的作用为静态猝灭且有单一作用位点,同时热力学参数计算结果显示,KNGP和COX-2的结合过程中疏水作用是主要驱动力,且KNGP和COX-2结合的是由熵驱动的自发过程。同步荧光、三维荧光光谱和荧光探针结果显示COX-2中的酪氨酸与色氨酸的疏水环境发生变化,且其表面的疏水性减弱。KNGP与COX-2的分子对接显示,KNGP分子主要通过NH基团、C=O结构、吲哚和咪唑结构与COX-2活性中心的氨基酸残基形成氢键和疏水相互作用,并通过形成静电作用增强结合的稳定性。以上结果表明,KNGP能与COX-2的单一位点通过氢键和疏水相互作用结合形成复合物,并改变酶的二级结构来抑制其活性。This study aimed to reveal the mechanism of action of oligopeptides KNGP on cyclooxygenase-2(COX-2),and to explore the interaction between KNGP from yellow pond turtle peptides(YPTP)and COX-2.The IC_(50) values of YPTP,synthesized KNGP and RG were determined by UV spectrophotometry.The mechanism of interaction between KNGP and COX-2 was investigated by intrinsic fluorescence,synchronous fluorescence,three-dimensional fluorescence spectroscopic techniques and ANS fluorescence probe.The mode of action between KNGP and COX-2 was studied by molecular docking.The results showed that the IC_(50) values of YPTP,KNGP and RG were 0.609,0.046 and 0.056 mg/mL,respectively.The IC_(50) of KNGP was lower than that of the positive drug ibuprofen(IC_(50)=0.217 mg/mL),indicating that KNGP had a significant inhibitory effect on COX-2 enzyme.The intrinsic fluorescence results showed that KNGP had a static quenching effect on COX-2,and the action site was single.Meanwhile,the results of thermodynamic parameter calculations showed that hydrophobic interaction is the main driving force in the process of KNGP binding to COX-2,and KNGP binding to COX-2 is a spontaneous process driven by entropy.The results of synchronous fluorescence,three-dimensional fluorescence spectroscopic and ANS fluorescence probe showed that the hydrophobic environment of tyrosine and tryptophan in COX-2 changed,and the hydrophobicity of COX-2 surface was weakened.The molecular docking between KNGP and COX-2 showed that KNGP molecules formed hydrogen bonds and hydrophobic interactions with the amino acid residues of COX-2 active center mainly through NH,C=O structure,indole and imidazole structure,and enhanced the binding stability by forming electrostatic interaction.Therefore,the results showed that KNGP could form a complex with COX-2 at a single site through hydrogen bonding and hydrophobic interaction,and change the secondary structure of the enzyme to inhibit its activity.

关 键 词：荧光光谱 分子对接 COX-2 抗炎 寡肽 龟板 

分 类 号：TS201.2[轻工技术与工程—食品科学]