BIOPHYSICAL CHARACTERIZATION OF ALPHA CRYSTALLIN

性状：α-晶状体蛋白，是晶状体的主要蛋白质成分。 哺乳动物眼睛的透镜，存在于透镜细胞质中， 在3A：1B的同种型混合物中约40个亚基的聚集体 在人类身上。 由于透镜在整个 一个生物体的寿命，a-晶状体蛋白和其他透镜蛋白必须（a） 结构稳定，在一段时间内抗变性， 年或数十年;（B）必须存在而无超聚集， 足够的量，以显著提高 透镜;和（c）必须足够小和离散，以使透镜 在可见光光谱中的透明性。 最近发现， Horwitz认为，α-晶状体蛋白与热休克有关， 蛋白质家族，它可以以伴侣线的方式发挥作用， 防止部分变性蛋白质的超聚集可以解释 为什么它被“招募”为透镜蛋白。 它存在于所有的 主要的非晶状体组织，但仅在透镜中有两种亚型 晶体蛋白的混合物 长期目标是 因此，研究的目的是描述独特的结构和 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的发生。 在下一次拨款中 具体目标是（a）比较研究 天然的、重构的和 复性的α-晶状体蛋白聚集体，以表征 （B）比较结构和性能 α-晶状体蛋白同种型的功能特性， 理解为什么只有在透镜中两者才能被发现在一起。 一 各种生物物理和物理生化技术将被 用于这项工作，包括圆二色谱偏振光谱法 研究二级结构，快速液相色谱， 荧光能量转移，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.