Salt Bridge (Salt Linkage, Ionic Bond) (Molecular Biology)

A salt bridge is a pair of ionized groups with opposite charge that are in very close proximity in a macromolecule and contact each other at their van der Waals radii. The ion pair is stabilized by attractive electrostatic interaction and may even have some hydrogen bond character. Intra- and intermolecular salt bridges are frequently observed in proteins (1) and at protein-protein and protein-nucleic acid interfaces (2).