AGE & CATARACT RELATED CHANGES IN LENS PROTEIN STRUCTURE

透镜透明性是通过保持 细胞质蛋白和纤维细胞膜的均匀排列。 光散射最小化这两个层次的结构 规律性年龄和白内障相关的蛋白质变化， 膜，在相互作用性质或结构中，将 改变结构规则性，引起透镜混浊。蛋白 透镜中的浓度非常高， 对方.这种相互作用提供了结构规律性。在 相反，导致高分子量（HMW）的相互作用 聚集体破坏了结构的规则性。两者的机制 相互作用还没有得到很好的理解。HMW的形成 聚集体似乎是由蛋白质解折叠启动的， 转是由翻译后修饰引起的。过程 翻译后修饰导致 解折叠导致聚集导致不溶解。 的 聚集体可以是蛋白质-蛋白质或蛋白质-膜 互动这些事件最终导致透镜不透明。是 然而，翻译后修饰是如何展开的， 蛋白质，以及未折叠的蛋白质如何变得容易受到 聚合来此外，还需要确定， 不溶性蛋白质在散射光时变得如此有效， 不透明的透镜。在这项拟议的研究中， 正常的蛋白质相互作用将首先研究，然后， 它们被破坏并被HMW取代的机制 聚合来使用的技术包括荧光， 圆二色性和NMR。 这不仅是可能的-研究 蛋白质解折叠过程，但也有结构变化， 聚集和不溶性蛋白质。后者似乎是一个 光散射的重要贡献者，可以通过 前表面荧光和固态NMR。另一个重要 透镜混浊的一个因素是膜的变化。一个 增加的膜刚度不仅影响生物学特性， 功能，而且还会改变物理属性，例如 折射率 测量荧光各向异性， 微粘度将被用来理解增加的影响。 胆固醇和相关晶体蛋白。 这项拟议研究的意义在于，它提出了一些 重点研究了浓缩蛋白质溶液， 粉末和透镜凝胶。研究从稀溶液发展到 浓缩溶液，最后到透镜，可以提供信息 更接近于体内的真实情况

Lens transparency is achieved by maintain structural regularity of cytoplasmic proteins and uniform alignment of fiber cell membranes. Light scattering is minimized of these two levels of structural regularity. Age and cataractous dependent changes in proteins and membranes, in the interaction properties or in structures, will alter structural regularity and cause lens turbidity. Protein concentrations in the lens are, very high and they interact with each other. This interaction provides structural regularity. In contrast, the interaction leading to high molecular weight (HMW) aggregate disrupts the structural regularity. The mechanism of both interactions are not well understood. The formation of HMW aggregate appears to be initiated by protein unfolding, which in turn is caused by post-translational modifications. The process appears to be in the order; post-translational modifications leads to unfolding leads to aggregation leads to insolubilization. The aggregation could be either a protein-protein or a protein-membrane interaction. These events finally lead to lens opacity. It is unknown, however, how the post-translational modifications unfold protein, and how the unfolded protein becomes susceptible to aggregation. It also needs to be established how the aggregated and insoluble proteins become so effective in scattering light in the opaque lens. In this proposed study, the mechanism of the normal protein interactions will be studied first, and then the mechanism in which they are disrupted and replaced by HMW aggregation. The techniques to be used include fluorescence, circular dichroism and NMR. It is not only possible to -study the protein unfolding process, but also structural changes in the aggregated and insoluble proteins. The latter one appears to be an important contributor to light scattering and could be studied by front surface fluorescence and solid-state NMR. Another important factor for lens opacification is the change in membranes. An increased membrane rigidity not only affects the biological functions, but also changes the physical properties such as the refractive index. Measuring fluorescence anisotropy and microviscosity will be done to understand the effect of increased cholesterol and associated-crystallins. The significance of this proposed study is that it puts some emphasis on the study of concentrated protein solution,.protein powder and lens gel. Studies progressing from dilute solution to concentrated solution, and finally to lens, may provide information more relevant to what really occurs in vivo.