APBS

APBS is a powerful software package designed specifically for solving the Poisson-Boltzmann equation (PBE), which is widely used for modeling electrostatic interactions between molecular solutes in aqueous, salty media. The package is optimized for efficient evaluation of electrostatic properties that are applicable to simulations at a wide range of length scales. This makes it possible to investigate molecules with tens to millions of atoms, providing access to molecular simulations with incredibly high resolution and detail.

Continuum electrostatics, which is the foundation of APBS, plays a vital role in a range of biomolecular simulation applications, including the simulation of diffusional processes to determine ligand-protein and protein-protein binding kinetics. Additionally, APBS enables implicit solvent molecular dynamics of biomolecules, solvation, and binding energy calculations. These calculations assist in determining ligand-protein and protein-protein equilibrium binding constants to aid in rational drug design. Finally, the tool is used for biomolecular titration studies.

It's worth noting that APBS is distributed under a dual licensing scheme: the BSD License and MIT License. This ensures that individuals and organizations can use the software in a way that best meets their unique needs while remaining compliant with the various license requirements. Overall, APBS delivers a powerful, comprehensive solution for modeling electrostatic interactions in a range of biological systems.