Hi Huiying,
could you tell us which version of refmac you are using?
There has been an issue with torsion definitions in ligands NEVER
included in the refinement, even if they were in the cif (at least up to
Refmac_5.2.0019). I did have the same effect you had and wondered why.
(See list in October 2007)
Garib modified the code in a later version of 5.4 to allow you to
include all torsions from one residues by applying the following line:
restr tors include resi XXX
or to include only one specific definition in refinement
restr tors include resi XXX name var_1
In CCP4i you'll have to include this with the Developers Option to
include an external keyword-file. NOTE: Without doing anything, the
torsion definitions are still NOT used, which would explain the
behaviour you observe. This is a feature, not a bug ....
I'am not sure what the situation is in the current version, maybe Garib
should answer this?
Hope that helps,
Eckhard
Huiying Li schrieb:
I want to impose restraints during REFMAC refinement on the tortion
angles that control the tilting of an OH group from a plane in a ligand
bound to the protein. A few things that confused me:
1. In library cif file, should I just increase or decrease the
tor.value_angle_esd if I want to loosen or tighten the restraits?
2. What is the meaning of the last column in torsion angle parameters:
_chem_comp_tor.period, in cif file? In the PDB output file REFMAC also
lists the RMS and WEIGHT for the torsion angles, period 1 through 4.
3. In REFMAC gui under Geometric parameters, there is only one user
controlled weight for torsion. By changing the weight here, does it
change the torsion weight for all 4 periods?
Thanks in advance for the help.
Huiying
--
Eckhard Hofmann <[EMAIL PROTECTED]>
Ruhr-Uni Bochum
AG Proteinkristallographie, LS Biophysik, ND04/316
44780 Bochum
Tel: +49-(0)234/32-24463, Sekr. -24461, FAX: -14762
