Department of Applied Optics, ITMO University, 49 Kronverksky Pr., St.-Petersburg 197101, Russia.
International Research Institute of Bioengineering, ITMO University, 49 Kronverksky Pr., 197101 St.-Petersburg, Russia.
Biomolecules. 2019 Aug 12;9(8):359. doi: 10.3390/biom9080359.
Human serum albumin (HSA) is the most abundant protein in blood plasma. HSA is involved in the transport of hormones, fatty acids, and some other compounds, maintenance of blood pH, osmotic pressure, and many other functions. Although this protein is well studied, data about its conformational changes upon different denaturation factors are fragmentary and sometimes contradictory. This is especially true for FTIR spectroscopy data interpretation. Here, the effect of various denaturing agents on the structural state of HSA by using FTIR spectroscopy in the aqueous solutions was systematically studied. Our data suggest that the second derivative deconvolution method provides the most consistent interpretation of the obtained IR spectra. The secondary structure changes of HSA were studied depending on the concentration of the denaturing agent during acid, alkaline, and thermal denaturation. In general, the denaturation of HSA in different conditions is accompanied by a decrease in α-helical conformation and an increase in random coil conformation and the intermolecular β-strands. Meantime, some variation in the conformational changes depending on the type of the denaturation agent were also observed. The increase of β-structural conformation suggests that HSA may form amyloid-like aggregates upon the denaturation.
人血清白蛋白（HSA）是血浆中最丰富的蛋白质。HSA 参与激素、脂肪酸和一些其他化合物的运输，维持血液 pH 值、渗透压和许多其他功能。尽管这种蛋白质已经得到了很好的研究，但关于其在不同变性因素下构象变化的数据是零散的，有时甚至相互矛盾。这在 FTIR 光谱数据分析中尤其如此。在这里，我们系统地研究了 FTIR 光谱在水溶液中各种变性剂对 HSA 结构状态的影响。我们的数据表明，二阶导数卷积方法提供了对所得到的 IR 光谱的最一致的解释。研究了 HSA 的二级结构变化，这取决于在酸性、碱性和热变性过程中变性剂的浓度。总的来说，HSA 在不同条件下的变性伴随着α-螺旋构象的减少和无规卷曲构象和分子间β-折叠的增加。同时，也观察到了一些构象变化取决于变性剂类型的变化。β-结构构象的增加表明 HSA 可能在变性时形成类淀粉样聚集物。
