Is there a way to load trajectories that do not have box lines? I have trajectories from which most solvent and ions have been stripped. They were written with ptraj as amber coordinate files with the "nobox" option. I cannot get these to stay in register for MD movie. I do not have this problem for trajectories for which the box line has not been removed. Mike Bruist Dr. Michael F. Bruist Associate Professor of Biochemistry Department of Chemistry & Biochemistry Griffith Hall 147 University of the Sciences in Philadelphia Philadelphia, PA 19104-4495 Phone (Office & Voice Mail): (215) 596-8530 Department Phone: -8839 Department Fax: -8543 E-mail: m.bruist @usp.edu web page: http://tonga.usp.edu/bruist