Tertiary structure format Textual format Topology format AMBER top version 7 is written to distinguish it from old versions of AMBER Prmtop. Similarly to HDF5, it is a completely different format, according to AMBER group: a drastic change to the file format occurred with the 2004 release of Amber 7 (http://ambermd.org/prmtop.pdf) Prmtop Parm7 It can be modified manually, but as the size of the system increases, the hand-editing becomes increasingly complex. AMBER Parameter-Topology file format is used extensively by the AMBER software suite and is referred to as the Prmtop file for short. AMBER Prmtop file (version 7) is a structure topology text file divided in several sections designed to be parsed easily using simple Fortran code. Each section contains particular topology information, such as atom name, charge, mass, angles, dihedrals, etc. Prmtop7 AMBER Parm 1.22 AMBER Parm7