Salt bridges
In proteins, salt bridges occur between amino acid side-chains with opposite positive or negative full-electron charges, namely, (at neutral pH) Glu- or Asp- vs. Arg+ or Lys+. They can also occur between an inorganic ion, such as K+ or Cl-, and an amino acid side-chain.
A salt bridge is generally considered to exist when the centers of charge are 4 Å or less apart[1]. The energetic significance of such complementary charge pairs is a complex function of the local environment.
Putative salt bridges can be displayed by FirstGlance in Jmol.
ReferencesReferences
- ↑ Jeffrey, George A., An introduction to hydrogen bonding, Oxford University Press, 1997. Page 192.