Hi Alon, Yes, it makes sense that a larger probe radius could give a larger solvent-exposed surface area (SASA) because SASA is defined as where the center of the probe can go. See diagram in the "surface" help: <https://rbvi.ucsf.edu/chimerax/docs/user/commands/surface.html> Maybe you are thinking of solvent-exposed surface area (SESA, also shown in that diagram) which ChimeraX does not calculate. I hope this helps, Elaine ----- Elaine C. Meng, Ph.D. UCSF Chimera(X) team Resource for Biocomputing, Visualization, and Informatics Department of Pharmaceutical Chemistry University of California, San Francisco
On Dec 25, 2024, at 12:48 AM, Alon BenDavid via ChimeraX-users <chimerax-users@cgl.ucsf.edu> wrote:
Hi, I am trying to measure the exposed surface area of lysine residues in DNaseI (4AWN). I am using the “measure sasa” command. To my surprise, when I am increasing the probe radius (1.4 A, 5 A, 10 A etc.) I receive larger exposed surface area. Is that OK? Many thanks, Alon