Crystallization of halorhodopsin from Halobacterium sp. shark

The chloride-ion-pumping channel, halorhodopsin from Halobacterium sp. shark was detergent-solubilized and 3-D crystallized. Proteins were solubilized using the nonionic detergent n-octyl-beta-D-glucoside and were crystallized as thin-plate crystals with polyethylene glycol 4000 as a precipitant. The crystals belong to the space group P4(1)2(1)2 with unit-cell dimensions a=b=74.5 A and c=138.6 A. The diffraction pattern was slightly anisotropic. The best ordered crystal diffracted up to 3.3 A resolution along c axis with synchrotron radiation.