Salt bridges

From Proteopedia

Salt bridges occur between amino acid side-chains with opposite positive or negative full-electron charges, namely, Glu-, Asp-, Arg+, Lys+ (at neutral pH). A salt bridge is generally considered to exist when the centers of charge are 4 Å or less apart (Jeffrey, p. 192). The energetic significance of such complementary charge pairs is a complex function of the local environment.

Putative salt bridges can be displayed by