Abstract：
Human serum albumin (HSA) is the most abundant plasma protein of the circulatory system. It is a multidomain, multifunctional protein that, combining diverse affinities and wide specificity, binds, stores, and transports a variety of biological compounds, pharmacores, and fatty acids. HSA is finding increasing uses in drug-delivery due to its ability to carry functionalized ligands and prodrugs. All this raises the question of competition for binding sites occupancy in case of multiple ligands, which in turn influences the protein structure/dynamic/function relationship and also has an impact on the biomedical applications. In this work, the effects of interactive binding of palmitic acid (PA), warfarin (War) and ibuprofen (Ibu) on the thermal stability of HSA were studied using DSC, ATR-FTIR, and EPR. PA is a high-affinity physiological ligand, while the two drugs are widely used for their anticoagulant (War) and anti-inflammatory (Ibu) efficacy, and are exogenous compounds that accommodate in the deputed drug site DS1 and DS2, respectively overlapping with some of the fatty acid binding sites. The results indicate that HSA acquires the highest thermal stability when it is fully saturated with PA. The binding of this physiological ligand does not hamper the binding of War or Ibu to the native state of the protein. In addition, the three ligands bind simultaneously, suggesting a synergic cooperative influence due to allosteric effects. The increased thermal stability subsequent to binary and multiple ligands binding moderates protein aggregation propensity and restricts protein dynamics. The biophysics findings provide interesting features about protein stability, aggregation, and dynamics in interaction with multiple ligands and are relevant in drug-delivery.
摘要：
人血清白蛋白（HSA）是循环系统中最丰富的血浆蛋白。它是一个多域，多功能蛋白质，结合了不同的亲和力和广泛的特异性，绑定,商店,运输各种生物化合物，pharmacores,和脂肪酸。HSA由于其携带官能化配体和前药的能力而在药物递送中发现越来越多的用途。所有这些都提出了在多个配体的情况下结合位点占用的竞争问题，这反过来又会影响蛋白质的结构/动态/功能关系，并对生物医学应用产生影响。在这项工作中,棕榈酸（PA）的相互作用结合的影响，用DSC研究了华法林(War)和布洛芬(Ibu)对HSA的热稳定性,ATR-FTIR,和EPR。PA是一种高亲和力的生理配体，虽然这两种药物因其抗凝（War）和抗炎（Ibu）的功效而被广泛使用，并且是外源化合物,其适应于分别与一些脂肪酸结合位点重叠的被拒绝的药物位点DS1和DS2。结果表明,当用PA完全饱和时,HSA获得最高的热稳定性。该生理配体的结合不妨碍War或Ibu与蛋白质的天然状态的结合。此外,三个配体同时结合，表明由于变构效应的协同作用。二元和多种配体结合后增加的热稳定性缓和了蛋白质聚集倾向并限制了蛋白质动力学。生物物理学的发现提供了有关蛋白质稳定性的有趣特征，聚合，以及与多种配体相互作用的动力学，并且与药物递送有关。
