Hi, I am trying to rotate a molecule around a 3D density map. I had already saved the coordinates of the molecule relative to the map. However if I rotate the pdb file (creating a new pdb file with the rotated molecule) by rotating the coordinates around the origin (0,0,0) the new molecule is rotated around a a center that does not coincide with the center of the map. So I am confused about what are the relative positions of the origin for the map and pdb file. If I have an atom with pdb coordinates 0,0,0 should this atom appear at the center of the density map ?. Thanks Hernando -- ----------------------------------- Hernando Sosa Dept. of Physiology and Biophysics Albert Einstein College of Medicine 1300 Morris Park Av. Bronx NY 10461 phone (718) 430-3456 FAX (718) 430-8819 email hsosa@aecom.yu.edu -----------------------------------