Atomic force microscopy studies of icosahedral virus crystal growth.

Biological macromolecules and particularly viruses, provide excellent systems for the study of crystallization from solution because of their relatively large size. The kinetics of their crystallization is at least an order of magnitude less than for conventional systems, and their large size permits visualization, both of crystal lattices and individual particles, by techniques such as atomic force microscopy (AFM). This technique is especially powerful for biological macromolecules because it can be utilized in situ, in the crystallization mother liquor, over long periods of time without perturbing the growing crystals. We present here observations using AFM of the nucleation and growth of crystals of satellite tobacco mosaic virus, and some recordings as well of bromegrass mosaic virus. Correlations are made, where possible, with corresponding analyses using X-ray diffraction analysis.