Hi Murali, As far as I know, there is no definition of accessible surface area for an electron density map (and thus no way to calculate it in Chimera), only for atomic structures. I'll describe how to get it for atomic structures in my next message, replying to David. Best, Elaine ----- Elaine C. Meng, Ph.D. meng@cgl.ucsf.edu UCSF Computer Graphics Lab (Chimera team) and Babbitt Lab Department of Pharmaceutical Chemistry University of California, San Francisco http://www.cgl.ucsf.edu/home/meng/index.html On Mar 27, 2009, at 8:18 AM, Murali Ayaluru wrote:

Hi Elaine,

Thanks for the quick reply. I am aware of calculating the total surface area of the density maps using Chimera and has been using it for a long time. Now I am interested in the surface area that a solvent can access (in otherwords called - (solvent) accessible surface area). This is a part of the total surface area. Please mail me if this tool is available in Chimera.

Regards, Murali