Dear all, Is there a way to ask Coot to write pdb coordinate files with nucleic acid residue names in 'standard' PDB format? That is: DA, DC, DG, DT, A, C, G, T... Sorry, this may have been solved already, but I just found an old message (http://www.ysbl.york.ac.uk/~emsley/coot/mbox-2006/0227.html) with a perl solution put forward by Bill Scott. I wonder if a preference setting could be changed so there is no need to resort to external file editing. Thanks! -- Miguel Architecture et Fonction des Macromolécules Biologiques (UMR6098) CNRS, Universités d'Aix-Marseille I & II Case 932, 163 Avenue de Luminy, 13288 Marseille cedex 9, France Tel: +33(0) 491 82 55 93 Fax: +33(0) 491 26 67 20 e-mail: [log in to unmask] Web: http://www.pangea.org/mol/spip.php?rubrique2