A novel cataract-related mutation R10P in γA-crystallin increases susceptibility to thermal shock and ultraviolet radiation of γA-crystallin.

Congenital cataract is one of the most common causes of childhood blindness, typically resulting from genetic mutations. Over a hundred gene mutations associated with congenital cataract have been identified, with approximately half occurring in the Crystallin genes. In this study, we identified a novel γA-crystallin pathogenic mutation (c. 29G > C, p. Arg10Pro (R10P)), from a four-generation Chinese family with congenital cataract, and investigated its potential molecular mechanisms underlying congenital cataracts. We compared the protein structure and stability of purified the wild type (WT) and R10P under physiological conditions and environmental stresses (UV irradiation, pH imbalance, heat shock, and chemical denaturation) using spectroscopic experiments, SEC analysis, and the UNcle protein analysis system. The results demonstrate that γA-R10P has no significant impact on the structure of γA-crystallin on normal condition. However, it is more sensitive to UV irradiation at high concentrations and prone to aggregation at high temperatures. Therefore, our study reveals the crucial role of the conserved site mutation R10P in maintaining protein structure and stability, providing new insights into the mechanisms of cataract formation.