The structure of southern bean mosaic virus protein crystals.

Abstract From measurements on a series of electron micrographs of single crystals of the southern bean mosaic virus protein it is shown that their molecules are in a cubic close packed arrangement. The tetramolecular unit cube has the edge length a0 = 345 A corresponding to a dried particle diameter of 245 A. The various faces that appear on the crystals are identified and illustrated, and a possible relation suggested between their occurrence and the way the crystals have grown.