BIOPHYSICAL CHARACTERIZATION OF ALPHA CRYSTALLIN

描述：α-晶体蛋白，主要的蛋白质成分 哺乳动物眼睛的晶状体，存在于晶状体细胞质中 3A：1B异构体混合物中约40个亚基的聚集体 在人类身上。因为晶状体在整个过程中的发展方式 生物体、a-晶体蛋白和其他晶状体蛋白的寿命必须(A) 结构稳定，耐变性长达一段时间 几年或几十年；(B)必须存在，而不是在 足够的量来显著提高材料的折射率 透镜；和(C)必须足够小和足够离散，以使透镜 可见光光谱中的透明度。他的最新发现 Horwitz认为α-晶状体蛋白与热休克顺序相关 蛋白质家族，它可以以陪伴线的方式作用于 阻止部分变性蛋白质的超聚集可能解释了 为什么它被“招募”为晶状体蛋白质。它存在于所有 主要的非晶状体组织，但仅在晶状体中有两种异构体 一起发现的α-晶体蛋白。这样做的长期目标是 因此，研究是为了表征独特的结构和 α-晶状体蛋白的功能特性有助于长期 视觉功能和防止白内障形成的工作。在下一笔赠款中 期间，具体目的是(A)对比调查 原生的、重新构建的和 复性的a-晶体蛋白聚集体，以表征 它们的长期稳定性；以及(B)比较结构性和 α-晶体蛋白异构体的功能性质 理解为什么只有在镜头中，两者才能被发现在一起。一个 各种生物物理和物理生化技术将被 用于这项工作，包括圆二色光谱旋光法 为了研究二级结构，快速高效液相色谱， 荧光能量传递、同步辐射散射和衍射， 电子显微镜和流变仪。

DESCRIPTION: Alpha-crystallin, tha major protein component of the crystalline lens of mammalian eyes , exist in the lens cytoplasm as aggregates of approximately 40 subunits in an isoform mixture of 3A:1B in the human. Because of the way the lens develops throughout the lifetime of an organism, a-crystallin and other lens proteins must (a) be stable in structure and resistant to denaturation for a period of years or decades; (b) must be present without superaggregation in sufficient quantities to raise significantly the refractive index of the lens; and (c) must be small and discrete enough to enable lens transparency in the visible light spectrum. The recent discovery by Horwitz that a-crystallin is related in sequence to the heat shock protein family and that it can act in a chaperone-line fashion to prevent the superaggregation of partially denatured proteins may explain why it was "recruited" as a lens protein. It is present in all the major non-lenticular tissues, but only in the lens are the two isoforms of a-crystallin found together. The long-term objective of this research is therefore to characterize the unique structural and functional properties of a-crystallin that contribute to long-term visual function and work against cataractogenesis. In the next grant period, the specific aims are (a) to investigate comparatively the structural and functional properties of native, reconstituted, and renatured a-crystallin aggregates in order to characterize the basis for their long-term stability; and (b) to compare the structural and functional properties of the a -crystallin isoforms in order to understand why it is only in the lens that both are found together. A variety of biophysical and physical biochemical techniques will be employed for this work, including circular dichroism spectropolarimetry to study secondary structure, fast performance liquid chromatography, fluorescence energy transfer, synchrotron scattering and diffraction, electron microscopy, and rheometry.