Armstrong’s Exclusion-Zone SASA Formula and Model

The solvent-accessible surface area (SASA) of a molecule is a fundamental metric in computational biochemistry and structural biology. Existing models often rely on geometric approximations and may underrepresent exclusion zones caused by steric hindrance. This work introduces a new analytical approach—Armstrong’s Exclusion-Zone SASA Model—which incorporates atomic radii, bond lengths, and probe radii into a corrected effective radius. A derived exclusion-zone radius formula enables more accurate and computationally efficient SASA estimation. This model can be integrated into SASA workflows with minimal overhead, offering improvements over traditional models.