College of Chemistry and Chemical Engineering, Shenyang Normal University, Shenyang 110034, China.
Provincial Key Laboratory for Separation and Analysis of Complex Systems in Liaoning Universities, Shenyang Normal University, Shenyang 110034, China.
Int J Mol Sci. 2023 Mar 10;24(6):5317. doi: 10.3390/ijms24065317.
Myricetin (MYR) and myricitrin (MYT) are well recognized for their nutraceutical value, such as antioxidant, hypoglycemic, and hypotensive effects. In this work, fluorescence spectroscopy and molecular modeling were adopted to investigate the conformational and stability changes of proteinase K (PK) in the presence of MYR and MYT. The experimental results showed that both MYR and MYT could quench fluorescence emission via a static quenching mechanism. Further investigation demonstrated that both hydrogen bonding and van der Waals forces play significant roles in the binding of complexes, which is consistent with the conclusions of molecular modeling. Synchronous fluorescence spectroscopy, Förster resonance energy transfer, and site-tagged competition experiments were performed to prove that the binding of MYR or MYT to PK could alter its micro-environment and conformation. Molecular docking results revealed that either MYR or MYT spontaneously interacted with PK at a single binding site via hydrogen bonding and hydrophobic interactions, which is consistent with the results of spectroscopic measurements. A 30 ns molecular dynamics simulation was conducted for both PK-MYR and PK-MYT complexes. The calculation results showed that no large structural distortions or interaction changes occurred during the entire simulation time span. The average RMSD changes of PK in PK-MYR and PK-MYT were 2.06 and 2.15 Å, respectively, indicating excellent stability of both complexes. The molecular simulation results suggested that both MYR and MYT could interact with PK spontaneously, which is in agreement with spectroscopic results. This agreement between experimental and theoretical results indicates that the method herein could be feasible and worthwhile for protein-ligand complex studies.
杨梅素（MYR）和杨梅苷（MYT）以其具有营养保健价值而广为人知，如抗氧化、降血糖和降血压作用。在这项工作中，采用荧光光谱法和分子建模研究了 MYR 和 MYT 存在时蛋白酶 K（PK）的构象和稳定性变化。实验结果表明，MYR 和 MYT 均可通过静态猝灭机制猝灭荧光发射。进一步的研究表明，氢键和范德华力在复合物的结合中都起着重要作用，这与分子建模的结论一致。同步荧光光谱、荧光能量共振转移和位点标记竞争实验证明，MYR 或 MYT 与 PK 的结合可以改变其微环境和构象。分子对接结果表明，无论是 MYR 还是 MYT，都可以通过氢键和疏水相互作用自发地与 PK 在单一结合位点相互作用，这与光谱测量结果一致。对 PK-MYR 和 PK-MYT 复合物进行了 30ns 的分子动力学模拟。计算结果表明，在整个模拟时间内，PK 没有发生大的结构扭曲或相互作用变化。PK 在 PK-MYR 和 PK-MYT 中的平均 RMSD 变化分别为 2.06 和 2.15Å，表明两个复合物都具有出色的稳定性。分子模拟结果表明，MYR 和 MYT 都可以与 PK 自发相互作用，这与光谱结果一致。实验和理论结果之间的一致性表明，该方法可用于蛋白质-配体复合物的研究，是可行且有价值的。
