I am wondering if it is possible in Chimera to select between different chains in a multimer that are defined by the SEGID parameter in XPLOR. This appears on columns 77-80 of the PDB file, e.g. in this homotrimer: ATOM 1 N GLN 1 -2.276 -27.488 29.307 1.00 0.00 A ... ATOM 684 N GLY 1 4.365 -26.465 20.200 1.00 0.00 C --- ATOM 1357 N GLN 1 13.798 -26.207 29.441 1.00 0.00 E ... Atom selection results in picking up 3 atoms instead of 1, since Chimera expects the chain designation after the residue name. The XPLOR output is therefore not compatible with Chimera input requirements and I am wondering if there is a workaround. Many thanks for any suggestions. --------------------------------- Miriam Gochin Touro University California miriam.gochin@tu.edu 707-638-5463