Alpha Helix

Protein molecules - built from chains of amino acids - have the amazing ability to form themselves into structures. One of the commonest of these is the alpha helix. The chain is twisted round into a spiral and held in place with hydrogen bonds.

Most enzymes and other proteins contain sections of alpha helix

The variable parts of the amino acids stick out from the spiral. These interact with each other, or with the surrounding water, and make the chain bend into a specific shape. By combining different amino acids life is able to make lots of different shaped proteins.