The electron density map file in X-PLOR contains information
about the crystal unit cell, indexing of the map, and the actual
electron density map. Because helical structure does not have a
crystal unit cell, the unit cell parameters in the map file of
fiber_refin-map-statment are replace by the dimensions of
the electron density map:
= the length (Å) of the map in x direction.
The map file can be read by a modified version of MAPPAGE to
provide a “DSN6” file for FRODO. This modified version is
included in XPLOR distribution package from Brünger. The grid
size of the map is determined by the GRID parameter.
= the length (Å) of the map in y direction.
= the length (Å) of the map in z direction.