BIOPHYSICAL INVESTIGATIONS OF GAMMA-CRYSTALLINS

在过去的50年里， 年龄有某种形式的白内障。 白内障晶状体的典型治疗 手术切除后植入固定病灶 透镜。 在哺乳动物晶状体中，透镜的核心由一组水组成 称为γ-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 是存在高度序列和结构同源性 不同哺乳动物的γ-晶体蛋白，为了方便起见， 通常研究来自小牛的晶体蛋白。 γ-晶体蛋白 命名为I-IV，这是由于它们在磺丙基上的洗脱曲线 柱 存在单个γ-晶体蛋白的选择性合成 γ-IV主要在胎儿发育期间合成。 如果 将幼年哺乳动物的透镜冷却至4 ℃，透镜变得不透明。 这 在加热透镜时不透明性清除。 这种现象被称为“冷 白内障”，并涉及“冷沉淀在生理浓度。 已知的是，增加这些“冷”的温度的试剂可以用于治疗癌症。 “白内障”的形成，在整个透镜中诱导白内障的形成。 相反地， 可以使用降低冷性白内障形成温度的试剂 来清除化学诱导的白内障 因此，重要的是进一步表征生物物理行为 这些蛋白质。 这项研究将比较和对比生物物理 单个γ-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，研究他们的热变性过程，使用热 分析和光谱技术，并研究能量学 参与了它们的冷沉淀过程。

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.