Khanova Helen A, Markossian Kira A, Kurganov Boris I, Samoilov Alexander M, Kleimenov Sergey Yu, Levitsky Dmitrii I, Yudin Igor K, Timofeeva Antonina C, Muranov Konstantin O, Ostrovsky Michail A
Bach Institute of Biochemistry, Russian Academy of Sciences, Leninsky 33, 119071, Moscow, Russia.
Biochemistry. 2005 Nov 29;44(47):15480-7. doi: 10.1021/bi051175u.
Thermal denaturation and aggregation of beta(L)-crystallin from bovine lens have been studied using differential scanning calorimetry (DSC) and dynamic light scattering (DLS). According to the DLS data, the distribution of the beta(L)-crystallin aggregates by their hydrodynamic radius (R(h)) remains monomodal to the point of precipitating aggregates (sodium phosphate, pH 6.8; 100 mM NaCl; 60 degrees C). The size of the start aggregates (R(h,0)) and duration of the latent stage (t(0)) leading to the formation of the start aggregates have been determined from the light scattering intensity versus the hydrodynamic radius plots and the dependences of R(h) on time. The R(h,0) value remains constant at variation of the beta(L)-crystallin concentration, whereas the t(0) value increases with diminishing beta(L)-crystallin concentration. The suppression of beta(L)-crystallin aggregation by alpha-crystallin is connected with the decrease in the R(h,0) value and increase in the t(0) value. In the presence of alpha-crystallin the aggregate population is split into two components. The first component is represented by stable aggregates whose size remains constant in time. The aggregates of the other kind grow until they reach the size characteristic of aggregates prone to precipitation. The DSC data show that alpha-crystallin has no appreciable influence on thermal denaturation of beta(L)-crystallin.
利用差示扫描量热法（DSC）和动态光散射法（DLS）研究了牛晶状体β（L）-晶状体蛋白的热变性和聚集。根据DLS数据，β（L）-晶状体蛋白聚集体的流体动力学半径（R（h））分布在聚集体沉淀点（磷酸钠，pH 6.8；100 mM NaCl；60℃）之前保持单峰。从光散射强度与流体动力学半径的关系图以及R（h）随时间的变化关系中，确定了起始聚集体的大小（R（h,0））和导致起始聚集体形成的潜伏期（t（0））的持续时间。R（h,0）值在β（L）-晶状体蛋白浓度变化时保持恒定，而t（0）值随β（L）-晶状体蛋白浓度降低而增加。α-晶状体蛋白对β（L）-晶状体蛋白聚集的抑制作用与R（h,0）值的降低和t（0）值的增加有关。在存在α-晶状体蛋白的情况下，聚集体群体分为两个组分。第一个组分由稳定的聚集体代表，其大小随时间保持恒定。另一种聚集体不断生长，直到达到易于沉淀的聚集体的特征大小。DSC数据表明，α-晶状体蛋白对β（L）-晶状体蛋白的热变性没有明显影响。
