Carreón Yojana J P, Jaramillo-Granada A M, Fuentes-López D, Reyes-Figueroa A D, González-Gutiérrez J, Mercado-Uribe H
Facultad de Ciencias en Física y Matemáticas, Universidad Autónoma de Chiapas Tuxtla Gutiérrez Chiapas 29050 Mexico.
CONAHCYT CDMX Mexico.
RSC Adv. 2025 Jan 2;15(1):244-251. doi: 10.1039/d4ra04503c.
The hydration shell of a protein is so important and an integral part of it, that protein's structure, stability and functionality cannot be conceived in its absence. This layer has unique properties not found in bulk water. However, ions, always present in the protein environment, disturb the hydration shell depending on their nature and concentration. In this work, we study the effect of four alkali metal halides (LiCl, NaCl, KCl and CsCl) on a Bovine Serum Albumin (BSA) suspension. In order to investigate the influence of such ions on this protein, we use several experimental methods: dynamic light scattering, differential scanning calorimetry, thermogravimetry, Fourier transform infrared spectroscopy and image analysis. We found that Li and Na prevent protein aggregation. Moreover, the ion size affects the interaction with the secondary structure of the protein (Amide III band). Notably, for the smallest ion (Li), the water-ion interaction dominates over the Amide A band signature, contrasting with the other ions. We also differentiate between bulk and hydration water through the evaporation of protein suspensions.
蛋白质的水化层非常重要，是其不可或缺的一部分，没有它，蛋白质的结构、稳定性和功能就无法想象。这一层具有本体水中不存在的独特性质。然而，蛋白质环境中始终存在的离子会根据其性质和浓度干扰水化层。在这项工作中，我们研究了四种碱金属卤化物（LiCl、NaCl、KCl和CsCl）对牛血清白蛋白（BSA）悬浮液的影响。为了研究这些离子对这种蛋白质的影响，我们使用了几种实验方法：动态光散射、差示扫描量热法、热重分析法、傅里叶变换红外光谱法和图像分析。我们发现Li和Na可防止蛋白质聚集。此外，离子大小会影响与蛋白质二级结构（酰胺III带）的相互作用。值得注意的是，对于最小的离子（Li），水 - 离子相互作用比酰胺A带特征更为显著，这与其他离子形成对比。我们还通过蛋白质悬浮液的蒸发来区分本体水和水化水。
