Phase boundaries and liquid structure of concentrated eye lens protein mixtures

描述（由申请人提供）：白内障是世界范围内致盲的主要原因，是人体晶状体内光散射增加的最终结果。本研究旨在建立浓缩的晶状体水晶体蛋白混合物的多组分相图及其统计-热力学分子基础。将使用中子散射、x射线散射、光散射、统计热力学建模和计算机模拟(i)建立γ -晶体蛋白与α -晶体蛋白、α -晶体蛋白和α -晶体蛋白混合物的浓混合物的相图和光散射；（ii）用小角中子散射测量高度浓混合物中选择性氘化γ -晶体蛋白和α -晶体蛋白的晶体特异性液体结构。（iii）评价γ结晶素电荷对相边界位置、光散射强度、维里系数和液体结构的影响（iv）建立稀、浓α a和α b结晶素溶液及其混合物的维里系数、相互作用和液体结构。这些步骤是提供对晶体蛋白和晶体蛋白的浓缩混合物相图的良好分子理解的基本要素，因此对白内障的分子基础有影响。白内障是世界范围内致盲的主要原因，是人类晶状体内光线散射增加的最终结果。拟议的研究旨在进一步调查这种光散射的一个潜在来源的分子起源，这种光散射是由蛋白质之间的吸引力驱动的眼睛晶状体蛋白质的相位变化。然而，眼睛的晶状体包含了蛋白质的混合物，而这种相变现在被理解为不仅是由蛋白质之间的相互吸引引起的，而且也是由蛋白质之间的大小和其他性质的差异引起的。这项研究旨在帮助量化蛋白质特性的各种差异是如何导致光散射的。这将通过故意改变蛋白质的大小和电荷来实现，通过使用特殊的短波散射技术来帮助找出平均相邻的蛋白质分子类型，并通过研究在白内障中重要的某些晶状体蛋白质，α - a和α - b晶体蛋白的相变作用。通过发现晶状体正常和病变状态的详细分子起源，可以为改善白内障奠定坚实的基础，为社会提供一个更持久的健康方面的可能益处。此外，通过阐明控制眼球晶状体细胞拥挤内部的原理，更普遍地影响活细胞拥挤内部的原理将被发现，这些原理可能具有非常广泛的影响。

DESCRIPTION (provided by applicant): Cataract disease, the leading cause of blindness worldwide, is the end result of increased scattering of light within the human ocular lens. The proposed research seeks to establish the multi-component phase diagram of concentrated, aqueous eye lens crystallin protein mixtures, together with its statistical-thermodynamic molecular basis. Neutron scattering, X-ray scattering, light scattering and statistical thermodynamic modeling and computer simulation will be used (i) to establish the phase diagram and light scattering of concentrated mixtures of gamma crystallins with alphaA crystallin, alphaB crystallin and alphaAB mixtures, (ii) to measure, with small angle neutron scattering, the crystallin- specific liquid structure of selectively deuterated gamma and alpha crystallins in highly concentrated mixtures, (iii) to evaluate the influence of gamma crystallin charge on the phase boundary locations, the light scattering intensity, the virial coefficients and the liquid structure (iv) to establish the virial coefficients, interactions and liquid structure of dilute and concentrated alphaA and alphaB crystallin solutions and their mixtures. These steps are essential elements for providing a sound molecular understanding of the phase diagram of concentrated mixtures of gamma and alpha crystallin, and as such bear on the molecular underpinnings of cataract. Cataract disease, the leading cause of blindness worldwide, is the end result of increased scattering of light within the human ocular lens. The proposed research seeks to further investigate the molecular origins of one potential source of this light scattering, a change of phase of the eye lens proteins that has long been known to be driven by protein-protein attractions. The lens of the eye contains a mixture of proteins, however, and this phase transition is now being understood to result not only from protein-protein attractions, but also from differences in size and other properties between the proteins. This research aims to help quantify how various differences in protein properties lead to light scattering. This will be done by varying protein size and charge deliberately, by using special short-wavelength scattering techniques that can help find out which types of protein molecules are next to one another on average, and by investigating the role in the phase transition of certain lens proteins important in cataract, alpha-A and alpha-B crystallin. By finding the detailed molecular origins of the normal and the diseased state of the eye lens, a sound basis for ameliorating cataract can potentially be constructed, providing society with the possible benefits of one longer lasting aspect of health. Further, by elucidating the principles governing the crowded interior of the eye lens cells, principles that bear more generally on the crowded interiors of living cells stand to be discovered, principles that may have very broad impact.