PROTEIN AND VIRUS CRYSTAL-GROWTH ON INTERNATIONAL MICROGRAVITY LABORATORY-2

Two T = 1 and one T = 3 plant viruses, along with a protein, were crys tallized in microgravity during the International Microgravity Laborat ory-2 (IML-2) mission in July of 1994. The method used was liquid-liqu id diffusion in the European Space Agency's Advanced Protein Crystalli zation Facility (APCF). Distinctive alterations in the habits of Turni p Yellow Mosaic Virus (TYMV) crystals and hexagonal canavalin crystals were observed. Crystals of cubic Satellite Tobacco Mosaic Virus (STMV ) more than 30 times the volume of crystals grown in the laboratory we re produced in microgravity. X-ray diffraction analysis demonstrated t hat both crystal forms of canavalin and the cubic STMV crystals diffra cted to significantly higher resolution and had superior diffraction p roperties as judged by relative Wilson plots. It is postulated that th e establishment of quasi-stable depletion zones around crystals growin g in microgravity are responsible for self-regulated and more ordered growth.