Toward Molecular-Scale Models of Congenital and Age-Related Cataract: a Concerted Computational and Experimental Approach

 描述（由申请方提供）：白内障是一种由晶状体蛋白溶解性丧失引起的眼透镜混浊，是全球失明的主要原因。拟议研究的总体目标是使用计算建模和一系列广泛的生物物理实验，在分子水平上获得对白内障形成的新见解，最终指导白内障预防和治疗新疗法的开发。驱动所提出的研究的主要假设是由点突变（在先天性白内障的情况下）或翻译后修饰（在年龄相关性白内障的情况下）引起的改变的蛋白质-蛋白质相互作用导致晶状体蛋白的聚集，这进而导致透镜中的透明度丧失。我们提出了一个协调一致的实验和计算研究的蛋白质结构，组织和聚集在解决方案的人γD-和γ S-晶体蛋白。我们将采用多尺度计算建模方法，包括蒙特卡罗和原子分子动力学模拟，并使用实验数据进行验证和改进（NMR、光散射和小角散射），以获得对稳定野生型γD-和γS-晶体蛋白浓缩溶液的蛋白质间相互作用的分子尺度洞察，或导致在与先天性白内障相关的变体的溶液中形成不溶性聚集体。同样的方法将应用于对模拟年龄相关性白内障中观察到的变化的γS-晶状体蛋白脱酰胺变体的首次系统计算和生物物理研究。一旦MC模拟、生物物理实验、小角散射测量以及溶液和固态NMR实验的协同应用已经开发用于单组分γ-晶状体蛋白溶液，该方法将被应用于确定α B-晶状体蛋白和野生型γ-晶状体蛋白及其白内障相关变体之间相互作用的分子水平描述。因此，我们将获得重要的洞察伴侣功能 以及α B-晶体蛋白维持相互作用的微妙平衡的能力，所述相互作用维持野生型γ-晶体蛋白溶液的透明度。

 DESCRIPTION (provided by applicant): Cataract, an opacification of the eye lens caused by a loss of solubility of the crystallin proteins, is a leading cause of blindness worldwide. The overarching goal of the proposed research is to use computational modeling and a broad suite of biophysical experiments to gain new insight into cataract formation on the molecular level that could ultimately guide the development of new therapies for cataract prevention and treatment. The primary hypothesis driving the proposed research is that altered protein-protein interactions, resulting from point mutations (in the case of congenital cataract) or post- translational modifications (in the case of age-related cataract), lead to aggregation of the crystallins which, in turn, leads to loss of transparency in the lens. We propose a concerted experimental and computational investigation of protein structure, organization, and aggregation in solutions of human γD- and γS-crystallins. We will employ a multiscale computational modeling approach, consisting of Monte Carlo and atomistic molecular dynamics simulations, validated and refined using experimental data (NMR, light scattering, and small angle scattering), to gain molecular-scale insight into the interprotein interactions that stabilize concentrated solutions of wild-type γD- and γS- crystallins, or lead to the formation of insolubl aggregates in solutions of variants associated with congenital cataracts. The same approach will be applied in the first systematic computational and biophysical investigation of deamidated variants of γS- crystallin that mimic the changes observed in age-related cataract. Once the concerted application of MC simulations, biophysical experiments, small angle scattering measurements, and solution and solid-state NMR experiments has been developed for single-component γ-crystallin solutions, the approach will be applied to the determination of a molecular-level description of the interactions between αB-crystallins and wild-type γ-crystallin and their cataract-related variants. Thus, we will gain crucial insight into the chaperone function of the αB-crystallins, as well as the ability of the αB-crystallins to maintain the delicate balace of interactions that maintains the transparency of solutions of wild-type γ-crystallins.