BIOPHYSICAL INVESTIGATIONS OF GAMMA-CRYSTALLINS

在过去的50年里，超过50%的美国人口 年龄有某种形式的白内障。白内障晶状体的典型治疗 包括手术切除，然后植入固定的焦点 镜头。 在哺乳动物的晶状体中，晶状体的核心由一组水组成 称为伽马晶体蛋白的可溶性蛋白质。这个蛋白质家族是 分子量约为20,000道尔顿的单体。那里 两者之间的序列和结构高度同源性 不同哺乳动物的伽马晶体蛋白，为了方便起见，伽马晶体蛋白- 从牛犊中提取的晶体蛋白通常被研究。γ-晶状体蛋白 命名为I-IV，因为它们在磺丙基上的洗脱图谱 纵队。有选择性地合成单个的伽马晶体蛋白 伽马-IV主要是在胎儿发育期间合成的。如果一个 幼年哺乳动物的晶状体被冷却到4摄氏度，晶状体变得不透明。这 当晶状体升温时，浑浊就会消失。这种现象被称为“冷” 白内障“和涉及生理浓度的冷沉淀。 已知的是，提高温度的药剂会使这些“冷” 白内障“形成，导致整个晶状体形成白内障。反之， 可以使用降低冷性白内障形成温度的药物 清除化学性白内障。 因此，进一步描述生物物理行为是很重要的 这些蛋白质中。这项研究将比较和对比生物物理 单个伽马晶体蛋白组分的行为。我们将探测地表 这些蛋白质的特性，特别是它们与 水，研究它们的热变性过程，使用两种热 分析和光谱技术，并研究能量学 在他们的冷沉淀过程中。

In excess of 50% of the population of the United States over 50 years of age has some form of cataract. Typical treatment for cataractous lenses involves their surgical removal followed by implantation of a fixed focus lens. In mammalian lenses, the core of the lens consists of a group of water soluble proteins termed gamma-crystallins. This family of proteins is monomeric with a molecular weight of approximately 20,000 daltons. There is a high degree of both sequence and structural homology present between the gamma-crystallins of different mammals and, for convenience, the gamma- crystallins from bovine calves are usually studied. The gamma-crystallins are named I - IV as a result of their elution profiles on a sulphopropyl column. There is selective synthesis of the individual gamma-crystallins with gamma-IV predominantly synthesized during foetal development. If a lens from a young mammal is cooled to 4oC, the lens becomes opaque. This opacity clears upon warming of the lens. This phenomenon is known as "cold cataract" and involves "cryoprecipitation at physiological concentrations. It is known that agents that increase the temperature at which these "cold cataracts" form, induce cataract formation in the whole lens. Conversely, agents that reduce the temperature of cold cataract formation can be used to clear chemically induced cataracts. It is therefore important to further characterize the biophysical behavior of these proteins. This study will compare and contrast the biophysical behavior of individual gamma-crystallins fractions. We will probe surface characteristics of these proteins in particular their interaction with water, investigate their thermal denaturation processes using both thermal analytical and spectroscopic techniques, and, investigate the enegetics involved during their cryoprecipitation.