Electrostatic Interactions Charged side chains in protein can interact favorably with an opposing charge of another side chain according to Coulomb's law: F=99 Dr2 Examples of favorable electrostatic interaction include that between positively charged Lys and negatively charged Glu. Salts have the ability to shield electrostatic interactions.Electrostatic Interactions Charged side chains in protein can interact favorably with an opposing charge of another side chain according to Coulomb’s law: Examples of favorable electrostatic interaction include that between positively charged Lys and negatively charged Glu. Salts have the ability to shield electrostatic interactions. 2 1 2 Dr q q F =