STRUCTURAL-PROPERTIES OF POLYDISPERSE BIOPOLYMER SOLUTIONS - A LIGHT-SCATTERING STUDY OF BOVINE ALPHA-CRYSTALLIN

We have measured <R(H)>z, <R(G)2>z1/2, and <M>w for individual fractions of the protein alpha-crystallin obtained by gel filtration of bovine lens nuclear extracts. A strong and monotonic decrease of <R(H)>z and <M>w with increasing elution volume could be observed, indicating a broad size distribution. The experimental results are quantitatively consistent with a polymerization of monomeric units into linear chains, which may have a certain degree of flexibility. Using theoretical expressions for <R(G)2> and R(H) originally derived for semiflexible polymers in solution, we can self-consistently analyse the data from static and dynamic light scattering, and from electron microscopy experiments. We thus obtain detailed information on the molecular weight distribution and the quaternary structure of alpha-crystallin in these solutions.