Frontiers in Bioscience-Landmark (FBL) is published by IMR Press from Volume 26 Issue 5 (2021). Previous articles were published by another publisher on a subscription basis, and they are hosted by IMR Press on imrpress.com as a courtesy and upon agreement with Frontiers in Bioscience.
The use of macroscopic electrostatic models to calculate the relative energetics of protonation states and the pH-titration properties of ionizable groups in proteins is described. These methods treat the protein as an irregularly-shaped low-dielectric object containing embedded atomic charges immersed in a high-dielectric (solvent) medium. The energetics of altering protonation states then involves the electrostatic work of altering the embedded atomic charges. The governing electrostatic equation is either the Poisson or linearized Poisson-Boltzmann equation, which generally requires numerical solution. A tutorial approach is taken, the main aim of which is a thorough understanding of the method.