PARAMETERS FOR THE 2-DIMENSIONAL CRYSTALLIZATION OF THE MEMBRANE-PROTEIN MICROSOMAL GLUTATHIONE TRANSFERASE

Various crystallization parameters were investigated to obtain two-dim ensional crystals of the detoxification enzyme microsomal glutathione transferase for structural analysis by electron crystallography. The p rotein was crystallized by reconstitution of the solubilized trimer in to proteoliposomes. Crystallization occurs when minimal amounts of lip id in the range of three lipid molecules per protein trimer are added to the dialysate. Once crystals were obtained, the effect of several p arameters on the crystallization was determined. The temperature and i nitial detergent concentration were found to be crucial parameters in influencing the size of the crystals, and conclusions could be drawn a bout the rate dependence of the crystallization process. Two highly or dered crystal forms, which are suitable for structural analysis by ele ctron crystallography, were obtained under the two-dimensional crystal lization conditions described here. (C) 1998 Academic Press.