Crystal growth of plant calmodulin

Abstract

Large amounts of maize calmodulin have been isolated, sufficient for crystal growth under different conditions. No crystals have ever been obtained of calcium-free calmodulin. Polyethyleneglycol 6000 as the precipitant lead to crystals of variable form. In the presence of 50%–60% (v/v) 2-methyl-2,4-pentanediol, needle-like or plate-like crystals were obtained up to 150 μm in length; the average isodiametric crystal size was 30×25×15 μm 3, prior to seeding. During the growth phase, the plate-like calmodulin crystals show faces (flat, stepped and kinked), similar to that as predicted by the periodic bond chain theory.