Three-dimensional structure of calmodulin

Abstract
The 3-dimensional structure of calmodulin [rat] was determined crystallographically at 3.0 .ANG. resolution. The molecule consits of 2 globular lobes connected by a long exposed .alpha.-helix. Each lobe binds 2 Ca ions through helix-loop-helix domains similar to those of other Ca-binding proteins. The long helix between the lobes may be involved in interactions of calmodulin with drugs and various proteins.