SPECTRAL ANALYSIS OF THE EFFECTS OF CALCIUM ION ON ALPHA CRYSTALLIN CONFORMATION

钙离子对α晶状体蛋白构象影响的光谱分析

• 批准号: 7547685
• 负责人: KENNETH HICKS
• 金额: $ 8.27万
• 依托单位: NORFOLK STATE UNIVERSITY
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/7547685
• 关键词: calcium ion; circular dichroism; conformation; crystallins; infrared spectrometry; minority institution research support; molecular chaperones; protein structure

The long-term objective of this project is to determine the effects of the presence of calcium ion on the configuration of the ocular lens protein alpha-crystallin. Ocular lens transparency depends on the specific packing of proteins that are synthesized. It has been shown that a-crystallin, a major protein component of the ocular lens, plays an important role in maintaining the transparency of the lens. It prevents heat-induced and photo-aggregation of other crystallins and enzymes by acting like a molecular chaperone. The chaperone-like activity of a-crystallin is believed due to the protein providing properly placed hydrophobic surfaces upon which the damaged protein interacts. It is thought that this chaperone-like behavior may be important in preventing cataract formation. Since it has been discovered that a-crystallin acts as a molecular chaperone under various denaturing conditions, research has focused on determining this mechanism of action that is thought to be protein conformation dependent. It is of interest to determine conditions which bring about this reduction in the chaperone ability of a-crystallin. It is hypothesized that acrystallin's configuration, and thus its chaperone-like behavior, is affected when its configuration is altered under stress conditions such as exposure to near-UV radiation. This proposal (prepared in collaboration with Dr. Lisa Hibbard (Spelman College) sets forth studies to investigate the effects of solvent ionic strength on the configuration and chaperone-like activity of a-crystallin and the lens structural protein, b-crystallin. Since it has been recently proposed that calcium binding may have either a deleterious or pivotal role in the chaperone-like behavior of a-crystallin depending on the concentration of ion present, ionic strength studies are relevant as it is known that the concentration of certain ions, in particular Na+ and Ca2+, can vary under given conditions in the ocular lens, particularly those in which cataracts are present. The combination of increased solvent ionic strength and exposure of aqueous solutions of a-crystallin to UV-A radiation will also be studied. It is of interest to determine whether the varying solvent conditions and exposure to UV radiation affects the ability of a-crystallin to protect b-crystallin upon heating. The project will study the effects of calcium ion on native and damaged protein conformation using both FTIR (and deconvoluted peak data) and far-UV CD spectra (done at Spelman College).

该项目的长期目的是确定钙离子的存在对 眼镜蛋白α-晶状蛋白的构型。眼镜透明度取决于特定 合成的蛋白质的包装。已经表明，a-晶状蛋白是一个主要蛋白质成分 眼镜在维持镜头的透明度中起着重要作用。它可以防止热诱导 以及其他结晶蛋白和酶的照片聚集，就像分子伴侣一样。这 由于蛋白质提供了适当的疏水性，因此人们认为A-晶状体的伴侣样活性被认为 受损蛋白质相互作用的表面。人们认为这种类似伴侣的行为可能是 对于防止白内障形成很重要。由于已经发现a-晶链素充当 分子伴侣在各种变性条件下，研究重点是确定这一点 被认为是蛋白质构象的作用机理。确定 导致A-晶状体蛋白伴侣能力的降低的条件。假设Acrystallin的 当更改其配置时，配置以及其类似伴侣的行为会影响 在应力条件下，例如暴露于近紫外线辐射。该建议（合作准备 丽莎·希巴德（Lisa Hibbard）博士（斯佩尔曼学院）提出了研究以研究溶剂离子力量的影响 关于A-晶状体蛋白和透镜结构蛋白B-晶状体蛋白的构型和伴侣样活性。 由于最近有人提出钙结合在 A-晶状体蛋白的伴侣样行为，具体取决于存在的离子强度研究的浓度 众所周知，某些离子的浓度，尤其是Na+和Ca2+的浓度可能会有所不同 给定眼镜中的情况，尤其是存在白内障的镜头。结合 提高溶剂的离子强度和A-晶体溶液的水溶液暴露于UV-A辐射也将 被研究。确定变化的溶剂条件和暴露于紫外线辐射是很有趣的 会影响A-晶状体在加热时保护B-晶状体蛋白的能力。该项目将研究 使用FTIR（和反价峰数据）和 Far-UV CD光谱（在Spelman College完成）。