The Generalized Born (GB) model offers a convenient way of representing electrostatics in complex
macromolecules like proteins or nucleic acids. The computation of atomic GB radii is currently performed
by different non-local approaches involving volume or surface integrals. Here we obtain a non-linearsecond-order partial differential equation for the Generalized Born radius, which may be solved using to the reaction field obeys Laplace’s equation. The equation admits as particular solutions the correct GB
local iterative algorithms. The equation is derived under the assumption that the usual GB approximation
radii for the sphere and the plane. The tests performed on a set of 55 different proteins show an overall
agreement with other reference GB models and ‘‘perfect’’ Poisson–Boltzmann based values.
