5.2.1.1 Primary structure

5.2.1.1 Primary structure

The primary structure is formed mostly by covalent peptide bonds linking the α-carboxyl carbon of each amino acid with the α-amino nitrogen of the next amino acid.mone or more covalent disulphide (-S-S-) bonds may also be involved in the primary structure whereever the peptide chain carries a cystine formed by such an S-S linkage between the side chain SH groups of two cystein residues of the same chain.

The sequence of the different amino acids is called the primary structure of the peptide or protein, which comprises the order of amino acids in the polypeptide chain of which a protein is formed, the properties of the covalent bonds joining the amino acids, their position and number: It includes the location of any disulfide bond. Counting of residues always starts at the N-terminal end (NH2-group), which is the end where the amino group is not involved in a peptide bond. The primary structure of a protein is determined by the gene corresponding to the protein.

 

    -Lys-Ala-His-Lys-Val- Ala- Leu-Gly-

   (Primary structure- amino acid sequence in a polypeptide chain)

Last modified: Saturday, 31 March 2012, 7:06 AM