This server calculates contacts between macromolecules
(protein and nucleic acids) at the one hand and co-factors,
ligands, drugs and ions at the other.
A contact is defined as two atoms for which the distance between
the Van der Waals surfaces is less than 1.0 Ångstrom.
WHAT IF uses the following Van der Waals radii: C:1.8 Ångstrom;
O:1.4 Ångstrom; N:1.7 Ångstrom; S:2.0 Ångstrom.
If you have detected any error, or have any question or suggestion,
please send an Email to Gert Vriend.
Roland Krause, Maarten L Hekkelman, Jens E Nielsen,