Dear Elaine, thanks for the useful fortran program, to do the renumbering out of chimera I also found another useful link: http://www.bioc.uzh.ch/antibody/Macros/Renumbering.html Best regards Sebastian -- Sebastian Kruggel Eppendorfer Weg 17d D 20259 Hamburg fon: +49 (0)40 4192 9579 mobil: +49 (0)151 1789 2232 e-mail: bustik at gmx.net