Pica Andrea, Graziano Giuseppe
Dipartimento di Scienze Chimiche, Università degli Studi di Napoli Federico II, Complesso Universitario di Monte Sant'Angelo, Via Cintia, Napoli, 80126, Italy.
Dipartimento di Scienze e Tecnologie, Università del Sannio, Via Port'Arsa 11, Benevento, 82100, Italy.
Biopolymers. 2018 Aug;109(10):e23076. doi: 10.1002/bip.23076. Epub 2017 Oct 25.
It is well established from the experimental point of view that the native state of globular proteins is more stable in heavy water than in water. No robust explanation, however, has been provided up to now. The application of the theoretical approach, originally devised to rationalize the general occurrence of cold denaturation, indicates that the magnitude of the solvent-excluded volume effect is slightly smaller in heavy water than in water and cannot explain the observed protein stabilization. The latter has to be due to the strength of protein-water van der Waals attractions which are weaker in heavy water due to the smaller molecular polarizability of D O compared with that of H O molecules. Since protein-water van der Waals attractions occur more in the denatured than in the native state, this contribution leads to a stabilization of the latter through a destabilization of the former.
从实验角度来看，球状蛋白质的天然状态在重水中比在水中更稳定，这一点已得到充分证实。然而，到目前为止，尚未有有力的解释。最初设计用于合理解释冷变性普遍现象的理论方法的应用表明，重水中溶剂排除体积效应的大小比水中略小，无法解释所观察到的蛋白质稳定性。后者必定归因于蛋白质 - 水范德华引力的强度，由于与H₂O分子相比，D₂O的分子极化率较小，所以这种引力在重水中较弱。由于蛋白质 - 水范德华引力在变性状态下比天然状态下更易发生，这种作用通过使前者不稳定而导致后者稳定。
