Andreasi Bassi F, Arcovito G, De Spirito M, Mordente A, Martorana G E
Istituto di Fisica, Università Cattolica del Sacro Cuore, Roma, Italy.
Biophys J. 1995 Dec;69(6):2720-7. doi: 10.1016/S0006-3495(95)80143-8.
The supramolecular aggregation of alpha-crystallin, the major protein of the eye lens, was investigated by means of static and dynamic light scattering. The aggregation was induced by generating heat-modified alpha-crystallin forms and by stabilizing the clusters with calcium ions. The kinetic pattern of the aggregation and the structural features of the clusters can be described according to the reaction limited cluster-cluster aggregation theory previously adopted for the study of colloidal particles aggregation systems. Accordingly, the average mass and the hydrodynamic radius of alpha-crystallin supramolecular aggregates grow exponentially in time. The structure factor of the clusters is typical of fractal aggregates. A fractal dimension df approximately 2.15 was determined, indicating a low probability of sticking together of the primitive aggregating particles. As a consequence, the slow-forming clusters assemble a rather compact structure. The basic units forming the fractal aggregates were found to have a radius about twice (approximately 17 nm) that of the native protein and 5.3 times its size, which is consistent with an intermediate molecular assembly corresponding to the already known high molecular weight forms of alpha-crystallin.
通过静态和动态光散射手段，对眼晶状体的主要蛋白质α-晶体蛋白的超分子聚集进行了研究。通过生成热修饰的α-晶体蛋白形式并利用钙离子稳定聚集体来诱导聚集。聚集的动力学模式和聚集体的结构特征可以根据先前用于研究胶体颗粒聚集系统的反应受限簇-簇聚集理论来描述。据此，α-晶体蛋白超分子聚集体的平均质量和流体动力学半径随时间呈指数增长。聚集体的结构因子是分形聚集体的典型特征。确定了分形维数df约为2.15，这表明原始聚集颗粒聚集在一起的概率较低。因此，形成缓慢的聚集体组装成相当致密的结构。发现形成分形聚集体的基本单元的半径约为天然蛋白质半径的两倍（约17 nm），大小为其5.3倍，这与对应于已知的α-晶体蛋白高分子量形式的中间分子组装一致。
