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导致失明的主要原因，是人类晶状体内光线散射增加的最终结果。这项拟议的研究旨在建立浓缩的水眼晶状体蛋白蛋白质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、光散射和统计热力学模拟和计算机模拟(I)建立伽马晶体与αA晶体蛋白、αB晶体蛋白和αAB混合物的浓缩混合物的相图和光散射，(Ii)利用小角中子散射测量在高浓度混合物中选择性地氢化的伽马晶体和α晶体蛋白的晶体特定的液体结构，(Iii)评估伽马晶体电荷对相边界位置、光散射强度、维里系数和液体结构的影响(Iv)建立维里系数，αA和αB晶体稀溶液和浓溶液及其混合物的相互作用和液体结构。这些步骤是提供对浓缩的伽马和α晶体蛋白混合物相图的良好分子理解的基本要素，因此与白内障的分子基础有关。白内障是世界范围内导致失明的主要原因，它是人类晶状体内光线散射增加的最终结果。这项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，这种光散射是眼睛晶状体蛋白质的相变化，长期以来一直被认为是由蛋白质-蛋白质吸引所驱动的。然而，眼睛的晶状体含有一种蛋白质的混合物，这种相变现在被理解为不仅是蛋白质-蛋白质吸引的结果，也是蛋白质之间大小和其他性质的差异造成的。这项研究旨在帮助量化蛋白质性质的各种差异如何导致光散射。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哪些类型的蛋白质分子平均彼此相邻，并通过研究在白内障中起重要作用的某些晶状体蛋白质，α-A和α-B晶体蛋白在相变中的作用。通过找到眼睛晶状体正常状态和疾病状态的详细分子起源，有可能构建一个改善白内障的可靠基础，为社会提供更持久的健康方面的可能好处。此外，通过阐明支配眼晶状体细胞拥挤内部的原理，可以发现更普遍地适用于活细胞拥挤内部的原理，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.