select selection, (resi 26+57+70 in chain a) and (resi 12 in chain d)^^^You want 'or' not 'and'. (Think of a Venn diagram - with 'and' you are looking for residues which are in both chain a and chain d, which is impossible)Cheers, Charlie
Thanks Charlie, select selection, (resi 26+57+70 in chain a) or (resi 12 in chain d) does what I want. I thought 'or' was exclusive. Thanks -- Sébastien Moretti http://igs.cnrs-mrs.fr/ CNRS - IGS 31 chemin Joseph Aiguier 13402 Marseille cedex
