Hi there, I want to compute accessible surface area for the backbone, as I want to compare the predicted amide deuteration between two conformations of a protein (I have PDBs for both). I tried with VADAR but the results are puzzling, I suspect they are not correct (the more open structure gets a lower score). Is there a way I can do something like that in Chimera ? In other word I need to compute how exposed to the solvent are the backbone atoms (in fact just the NH) and get a table for every position. Cannot seem to find a simple way to do that with Chimera... Thanks again for your help Cedric Cedric Govaerts, Ph.D. Structure et Fonction des Membranes Biologiques (SFMB) Universite Libre de Bruxelles Boulevard du Triomphe - CP 206/2 B-1050 Bruxelles (Belgium) Tel: +32-2-650.53.77 Fax: +32-2-650.53.82