State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu Province 214122, China; School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu Province 214122, China.
School of Chemical and Biomedical Engineering, Nanyang Technological University, 70 Nanyang Drive, Singapore 637457, Singapore.
Int J Biol Macromol. 2021 Jan 31;168:775-783. doi: 10.1016/j.ijbiomac.2020.11.135. Epub 2020 Nov 21.
The interaction between biomacromolecules and ligands has attracted great interest because of their biological properties. Calf thymus DNA (ctDNA) can interact with bioactive compounds to form complexes. Here, ctDNA-ligand complexes were studied using fluorescence, absorption, and infrared spectroscopy, circular dichroism, ABTS assay and competitive displacement. The binding constants of bioactive compounds at the intercalative site of ctDNA ranked in order kaempferol > apigenin > quercetin > curcumin > riboflavin, while the binding constants at minor groove sites ranked quercetin > kaempferol > naringenin ~ apigenin > hesperetin > curcumin ~ resveratrol ~ riboflavin > caffeic acid. CtDNA maintained stable B-form with an enhancement of base stacking and a decrease of right-handed helicity in the presence of these bioactive compounds, except for hesperetin and caffeic acid. Bioactive compounds preferentially bound to guanine bases and tended to transfer into a more hydrophobic environment upon complexation with ctDNA. The DNA complexation did not affect the ABTS· scavenging capacity of quercetin, kaempferol, resveratrol and apigenin but increased the ones of naringenin, caffeic acid, curcumin, hesperetin and riboflavin. The data gathered here should be useful to understand the binding modes of DNA with ligands for their potential application in pharmaceutical and food industries.
生物大分子与配体的相互作用因其生物特性而引起了极大的兴趣。小牛胸腺 DNA（ctDNA）可以与生物活性化合物相互作用形成复合物。在这里，使用荧光、吸收和红外光谱、圆二色性、ABTS 测定和竞争性置换研究了 ctDNA-配体复合物。生物活性化合物在 ctDNA 插入位点的结合常数依次为山奈酚>芹菜素>槲皮素>姜黄素>核黄素，而在小沟位点的结合常数依次为槲皮素>山奈酚>柚皮苷芹菜素>橙皮素>姜黄素白藜芦醇>核黄素>咖啡酸。在这些生物活性化合物存在下，ctDNA 保持稳定的 B 型构象，碱基堆积增强，右手螺旋减少，除了橙皮素和咖啡酸。生物活性化合物优先与鸟嘌呤碱基结合，并在与 ctDNA 络合时倾向于转移到更疏水的环境中。DNA 络合不会影响槲皮素、山奈酚、白藜芦醇和芹菜素的 ABTS·清除能力，但会增加柚皮苷、咖啡酸、姜黄素、橙皮素和核黄素的 ABTS·清除能力。这里收集的数据应该有助于理解 DNA 与配体的结合模式，以便将其潜在应用于制药和食品工业。
