Amino acid residue

Amino acid residue is the part of an amino acid that remains after a molecule of water has been lost (an dehydration reaction) during the formation of a peptide bond. In the context of a protein structure, an amino acid residue refers to a single unit of a protein.

Structure

An amino acid residue consists of an amino group, a carboxyl group, and a side chain (R group). The side chain is what differentiates one amino acid residue from another and determines the properties of the residue and, consequently, the protein.

Role in Protein Structure

Amino acid residues play a crucial role in the structure and function of proteins. The sequence of amino acid residues in a protein, known as the primary structure, determines the protein's shape and function. The interactions between the side chains of the amino acid residues can cause the protein to fold into a specific three-dimensional shape, forming the secondary structure (such as alpha helix and beta sheet) and tertiary structure of the protein.

Post-Translational Modifications

Amino acid residues can undergo various post-translational modifications, which can affect the function of the protein. These modifications include phosphorylation, acetylation, methylation, and glycosylation, among others.

See Also

• Peptide bond
• Protein structure
• Post-translational modification