Two-dimensional rhodopsin crystals from disk membranes of frog retinal rod outer segments.

Abstract
From purified frog disc membrane, 2-dimensional crystals of rhodopsin were prepared by using the detergent Tween 80. The space group of the orthorhombic crystals is p22121; the unit cell dimensions are 47 .times. 151 .ANG.. Projection maps of negatively stained preparations were calculated to a resolution of .apprxeq. 22 .ANG.. The rhodopsin molecules are associated as dimers that appear to be slightly sigmoidal are 20-25 .ANG. in width and 70-80 .ANG. in length.