The linear sequence of amino acids within a protein is considered the primary structure of the protein. Proteins are built from a set of only twenty amino acids, each of which has a unique side chain.

The enormous progress over the past decade in analytical techniques to study large macromolecules has revealed a much greater diversity in protein primary structure than predicted based on the use ...

Proteins have four levels of structure: primary (amino acid sequence), secondary (local folding patterns like alpha helices and beta sheets), tertiary (overall 3D shape), and quaternary (assembly of ...

The sequence of amino acids in the chain determines how the chain will fold up to make the protein, so different proteins have different three-dimensional shapes. The three-dimensional shape of a ...