Calmodulin EF Hand

Helix - Loop - Helix

Here is the structure of amino acids 118-148 of human calmodulin. This proteins binds calcium and modulates many intracelluar processes - it is a calcium modulatory protein (or calmodulin). Shown is a helix-loop-helix supersecondary structure motiff. Calcium (shown in spacefill rendering) is bound in the loop and is coordinated to Glu side chains protruding in from the loop

Wire Frame


Backbone and side chains 

Ca2+ and side chain interactions - notice the carboxyl Os interacting with the calcium 

Cartoon showing hydrogen bonds

Cartoon and Wireframe

Dot surface and Wireframe