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What are salt bridges in protein structure?

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Peptide — Protein The molecular structure of a peptide (a small protein) consists of a sequence of amino acids.

In protein biochemistry, salt bridges are non-covalent bonds formed by the electrostatic attraction between oppositely charged amino acid side chains. Specifically, they occur between the negatively charged side chains of aspartic acid or glutamic acid and the positively charged side chains of lysine or arginine.1

These interactions are a key component of a protein's tertiary structure, contributing to the overall folding and stability of the molecule. Because salt bridges rely on the attraction between charged groups, they can be disrupted by the addition of salts to a solution; the salt ions interact with the protein's charged side chains, effectively preventing the formation of these bridges.12