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178 华 中 农 业 大 学 学 报 第 41 卷

相互作用的荧光光谱研究［J］. 高等学校化学学报，2009，30 and ibuprofen by fluorescence spectrometry［J］.Chemical journal
（6）：1095-1100.SUN Y T，ZHANG Y P，BI S Y，et al.Studies of Chinese universities，2009，30（6）：1095-1100（in Chinese
on the interaction for bovine serum albumin with phenylbutazone with English abstract）.

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

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

Abstract This study aimed to reveal the mechanism of action of oligopeptides KNGP on cyclooxy⁃
genase-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 spec⁃
trophotometry.The mechanism of interaction between KNGP and COX-2 was investigated by intrinsic fluo⁃
rescence，synchronous fluorescence，three-dimensional fluorescence spectroscopic techniques and ANS flu⁃
orescence probe.The mode of action between KNGP and COX-2 was studied by molecular docking.The re⁃
sults showed that the IC 50 values of YPTP，KNGP and RG were 0.609，0.046 and 0.056 mg/mL，respec⁃
tively.The IC 50 of KNGP was lower than that of the positive drug ibuprofen（IC 50=0.217 mg/mL），indicat⁃
ing 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 hydro⁃
phobic interaction，and change the secondary structure of the enzyme to inhibit its activity.
Keywords fluorescence spectrum；molecular docking；COX-2；anti-inflammatory；oligopeptides；

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