Hi Elaine, I'm trying to calculate the solvent accessible surface area for several lysine residues in a protein to evaluate which are most likely to be free on the surface for functionalization. My thought was to just calculate the SAS area and rank order them. When I select just the primary amine of all the lysine residues and go to the reply log I get several numbers in a row under SAS and I'm not sure which are correct. These numbers don't seem to change if I select different residues so I'm not sure how to get the SAS values just for my lysine amines. Thanks, Dave -------------------------------------------------------- David Chenoweth NIH Postdoctoral Fellow Swager Research Group Massachusetts Institute of Technology Chemistry Department, 18-053 77 Massachusetts Avenue Cambridge, MA 02139 Email: dcheno@mit.edu Lab Phone: 617-258-6537 --------------------------------------------------------