FGF
CELL 30.9,33.4,35.9,59.5,72.0,75.6 FO fgfnat.hkl RESOLUTION 20 4 SET B 0.0 KSOL 0.8 INCLUDE fgf.seq COMBINE XYZ CONSTANT B CONSTANT OCC WEIGHT RFACTOR 0.0010 WEIGHT BOND 0.8 ANGLE 1.3 TORSION 0 WEIGHT TRIGONAL 2 PLANE 5 CONTACT 0 BCORREL 1.0
Fiberblast Growth Factor crystals grow in space group P1. Since P1 is the default space group one is not required to enter symmetry operators in the control file.
This control file indicates rigid-body refinement of the positions of the
atoms in the model. Both the temperature factors and occupancies are held
constant. Since the resolution limit was reduced to 4Å TNT was unable
to properly scale the data sets. The SET statement was used to force
B equal to 0.0 and 
equal to 0.8. Given this restriction TNT generates
proper values for the other scale factors.
The weights of the stereochemical restraints are unimportant except for that of the bad contacts. In the early stages of a Molecular Replacement rigid-body refinement the loops on the surface of the molecule are unreliable and it is probably not wise to use these overlaps in the positioning of the molecule. The CONTACT weight should be set to zero.