运用NMR研究白蛋白与脂肪酸的相互作用

脂肪酸在哺乳动物的能量代谢中发挥着至关重要的作用，同时也是合成细胞膜磷脂和其他生物活性化合物的重要物质.脂肪酸在血液中的溶解度很低，主要以与蛋白质结合状态存在，白蛋白是游离脂肪酸的主要运输者和储存者.因此，研究脂肪酸和白蛋白的相互作用具有非常重要的医学和生物学意义.本文主要利用基于核磁共振（NMR）的组氨酸选择性检测技术T₂W-RD-WaterLOGSY研究天然同位素丰度人血清白蛋白（HSA）与脂肪酸的相互作用，结果发现脂肪酸结合前后，HSA的特征组氨酸谱图变化明显，部分组氨酸信号的相对强度随脂肪酸浓度的增加而不断减小，相应的滴定曲线分析表明HSA表面有两个强的脂肪酸结合位点.此外，部分谱线的化学位移变化说明HSA和脂肪酸的强结合还会引发HSA相应的构象变化.

Interactions Between Albumin and Fatty Acids Studied by NMR Spectroscopy

Fatty acids are important substrates for the synthesis of membrane phospholipids and other bioactive compounds, and thus play vital roles in mammalian energy metabolism. Fatty acids often bind to proteins in the blood. Albumin is a major carrier and depot of free fatty acids. In this paper, the interactions between human serum albumin (HSA) and fatty acids were studied using nuclear magnetic resonance (NMR)-based histidine selective detection technology T₂W-RD-WaterLOGSY. The spectra of HSA before and after fatty acids binding were compared. It was found that signals of the characterized His in HSA changed significantly with the addition of fatty acids. Two high-affinity binding sites between the HSA and fatty acids were identified from the titration curve. It was also demonstrated that binding to fatty acids could induce conformation changes for HSA.