The primary structure of a protein is also its amino acid sequence. This information determines the ultimate structure and function of a protein.
Proteins are made of chains of amino acids joined through peptide bonds forming the primary sequence of the protein. The primary amino acid sequence of a protein determines the three-dimensional structure that the protein will fold into. In addition, scientists can use the primary sequence to identify many functional attributes a protein will have, such as enzyme active sites, ligand and metal binding sites, motifs, and domains. Finally, protein sequences are used to study protein families within a species and taxonomic relationships between species. Because of this, several methods have been developed to determine the primary sequence of a protein, both from the amino acid sequence itself and from the gene or mRNA that encodes the protein.