Department of Physics, Instituto de Biociências, Letras e Ciências Exatas (IBILCE), UNESP, São José do Rio Preto 15054-000, Brazil.
Multiuser Center for Biomolecular Innovation (CMIB), Instituto de Biociências, Letras e Ciências Exatas (IBILCE), UNESP, São José do Rio Preto 15054-000, Brazil.
Int J Mol Sci. 2020 Mar 24;21(6):2241. doi: 10.3390/ijms21062241.
The human Respiratory Syncytial Virus (hRSV) is the most frequent agent of respiratory infections in infants and children with no currently approved vaccine. The M protein is an important transcriptional antitermination factor and a potential target for viral replication inhibitor development. Hesperetin (HST) and hesperidin (HSD) are flavonoids from the flavanone group, naturally found in citrus and have, as one of their properties, antiviral activity. The present study reports on the interactions between hRSV M and these flavanones using experimental techniques in association with computational tools. STD-NMR results showed that HST and HSD bind to M by positioning their aromatic rings into the target protein binding site. Fluorescence quenching measurements revealed that HST had an interaction affinity greater than HSD towards M. The thermodynamic analysis suggested that hydrogen bonds and van der Waals interactions are important for the molecular stabilization of the complexes. Computational simulations corroborated with the experimental results and indicated that the possible interaction region for the flavonoids is the AMP-binding site in M. Therefore, these results point that HST and HSD bind stably to a critical region in M, which is vital for its biological function, and thus might play a possible role antiviral against hRSV.
人呼吸道合胞病毒（hRSV）是婴儿和儿童呼吸道感染最常见的病原体，目前尚无批准的疫苗。M 蛋白是一种重要的转录终止因子，也是病毒复制抑制剂开发的潜在靶标。橙皮素（HST）和橙皮苷（HSD）是类黄酮中的黄酮类化合物，天然存在于柑橘类水果中，具有抗病毒活性等特性。本研究采用实验技术结合计算工具，报道了 hRSV M 与这些类黄酮之间的相互作用。STD-NMR 结果表明，HST 和 HSD 通过将其芳环定位到靶蛋白结合位点与 M 结合。荧光猝灭测量表明，HST 与 M 的相互作用亲和力大于 HSD。热力学分析表明，氢键和范德华相互作用对复合物的分子稳定性很重要。计算模拟与实验结果一致，并表明类黄酮的可能相互作用区域是 M 中的 AMP 结合位点。因此，这些结果表明 HST 和 HSD 稳定地结合到 M 中的一个关键区域，该区域对其生物学功能至关重要，因此可能在抗 hRSV 方面发挥抗病毒作用。
