CRYSTALLIZATION OF SATELLITE TOBACCO MOSAIC-VIRUS .2. POSTNUCLEATION EVENTS

Quasi-elastic light scattering (QELS) was used to investigate nucleation and post nucleation events in the crystallization of satellite tobacco mosaic virus (STMV). The diameter of monomer STMV was measured to be almost-equal-to 16 nm, which corresponds well with data from electron microscopy and X-ray diffraction results. The data suggests that the rate limiting factor in STMV crystal growth is the diffusion of virus clusters to the growing crystal nucleus rather than the probability of incorporation. Our experiments demonstrate that for STMV, the aggregation process leading to crystal formation is distinctly different from that producing amorphous precipitate. The aggregation rate for crystallization is substantially higher with a power law exponent of n almost-equal-to 0.33-0.54. while that associated with eventual amorphous precipitate was in the range of n almost-equal-to 0.1-0.2. Our results provide additional evidence that QELS can be a useful tool for the rapid and nondestructive determination of the ultimate fate of solutions supersaturated with respect to macromolecules.