PHOTON-CORRELATION SPECTROSCOPY AND LIGHT-SCATTERING OF EYE LENS PROTEINS AT HIGH-CONCENTRATIONS

The bovine eye lens protein, .alpha.L crystallin, was studied with photon correlation spectroscopy and statical light scattering in the concentration range up to 200 g/1 in different solvent conditions. At higher concentration (c [concentration] > 70 g/1) the scattering behavior is quite complicated, which results in nonexponential correlation functions. Three methods were used for the analysis of these correlation functions, namely, cumulantananlysis, sum of 2 exponentials analysis and exponential sampling method. These methods gave very similar results. The highly concentrated solutions contain 2 scattering entities: the single .alpha.L crystallin and a rather heterogeneous population of large clusters. The statical light-scattering experiments can be interpreted in the same way and gave consistent results for the dimensions of the large scattering units. The formation of these clusters, which are strong light scatters, is superimposed on an increasing degree of correlation between the bulk of the .alpha.L-crystallins, resulting in a net decrease of light scattering as a functin of concentration.