ZMM searches optimal structures in the space of generalized coordinates: torsion angles, bond angles, bond lengths, positions free molecules and ions, and orientation of free molecules. Any generalized coordinate may be kept fixed. Molecules and fragments that are not expected to undergo significant conformational changes may be treated as rigid bodies.
Popular molecular modeling programs usually work in the space of Cartesian coordinates of atoms. During energy minimization of a big system, many Cartesian coordinates-variables move collectively. For example, rotation of a benzene ring around the C-Ph bond in the Cartesian-coordinates space involves collective motion of 33 variables. In the generalized-coordinates space, this rotation involves variation of just one torsion angle. In ZMM, any fragment of a molecular system may be treated as either rigid or flexible. The generalized-coordinates method saves large computational resources if only a small part of a system is considered flexible. Examples are ligand-protein and protein-protein interactions. The savings occur because the sampling space is reduced and because molecular interactions within rigid fragments are not computed.
- ZMM runs on Windows 2000, XP, 7, 10, Mac-OS, UNIX, and Linux
- ZMM can be used via the command-line interface
- ZMM can also be used at Windows via a graphical user interface