I saw an earlier post (Dec. 29, 2008; Digest vol. 68, issue 28) in which Elaine Meng described a procedure for calculating surface area for selected atoms. I did this for atoms on chain A that were selected as contacting atoms on neighboring chain B, but the sum(atom.areaSES) probably includes area buried within the chain A, not just between the 2 chains. I tried checking this by calculating the sum(atom.areaSES) for chain A (all atoms in A) in the whole model, then again for a model from which chain B was deleted before calculating the surface. However, the results indicated a larger areaSES for chain A in the absence of chain B! There were some errors reported in calculating the surfaces; perhaps this contributed. Is there a better way to calculate the buried surface on 1 chain due to contacts with a 2nd chain? Thanks, Tom Duncan