HEWL
CELL 28 62.9 60.5 90 90.8 90
INCLUDE /usr/local/tnt/data/symmetry/p21.dat
FO hewl.hkl
RESOLUTION 4
SET KSOL 0.8 ! Data will not scale properly without
! this SET card even to the full
! resolution of 2.2A.
INCLUDE pdb1lym.seq
CLUSTER N RESIDUE 1 - 91 CHAINS A B
CLUSTER C RESIDUE 92 - OXY CHAINS A B
COMBINE XYZ A|1 - 91
COMBINE XYZ A|92 - OXY
COMBINE XYZ B|1 - 91
COMBINE XYZ B|92 - OXY
CONSTANT B
CONSTANT OCC
WEIGHT RFACTOR 0.007
WEIGHT BOND 1.0 ANGLE 1.0 TORSION 0.0
WEIGHT TRIGONAL 5.0 PLANE 10.0 CONTACT 0.0 BCORREL 1
This control file indicates rigid-body refinement for each of the two domains of hen egg white lysozyme. In this crystal form there are two molecules in the asymmetric unit. As usual they are named A and B.
The first COMBINE statement defines the N terminal domain of chain A, containing residues 1 through 92, as one rigid-body. The second domain contains residues 92 through OXY and is made a rigid-body with the second COMBINE statement. (OXY is the name of the final residue of a polypeptide chain and contains the lone oxygen at the C terminus.) The other two COMBINE statements define the equivalent rigid bodies for chain B.
The resolution limit was dropped to 4Å and therefore a SET statement
forcing the value of 
was required. As the note in the control file
states this SET statement is even required with all the data. This fact
indicates some problem with the data set and should be noted in the control
file in this fashion to prevent the problem from being forgotten.
Both the B factors and the
occupancies are held constant because the Steepest Descent method will only
allow one kind of parameter to vary at a time.