Amino Acid Chains

Folding

When several amino acids are joined together into a chain and then placed in water, they fold up into a particular shape. For example some chains will form spirals like the one shown here.

A protein is made of a long chain of amino acids joined end to end

Jobs

The job an enzyme can do depends on its shape. Its shape depends on the way it folds up. The way a chain folds up depends on the order in which amino acids are joined in the chain. So the process of life centers upon joining the right amino acids in the right order.

The different amino acids have different groups which stick out of the side of the chain like the branches of a tree. The central chain is flexible and when placed in water it rolls itself up into a definite and reproducible conformation, pulled into shape by hydrogen bonds between these side branches and the surrounding water molecules.

This miracle of self-organization is fundamental to the process of life, because the shape of an enzyme, and the position of specially active branches along the trunk, determines the powers that the enzyme displays.