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Re: [ccp4bb]: pvdw function
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one option is to work with a lower symmetry space group,
so that we can avoid co-incident crystal and molecular
axes. For eg: if the space group is P6122, refinment
can be done in P61.
One problem in this case is your asymmetric unit get
multiplied (depending on the space group). One should also
be cautious to treat the subunits with strict NCS relationship
hope this helps,
Indian Institute of Science
Bangalore 560 012 India.
On Wed, 11 Oct 2000, Manisha goel wrote:
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> *** CCP4 home page http://www.dl.ac.uk/CCP/CCP4/main.html ***
> Dear all !
> i am refining the structure of complex in which the ligand
> lies across the
> symmetry axis such that half portion of the ligand is generated upon
> itself due to symmetry (only half the molecule of ligand lies in one
> asymmetric unit, the other identicel half belongs to the symmetry realted
> i have generated only half the molecule but during refinement, the two
> halves are considered as short contacts by the programm and any further
> refinement keeps pushing them apart.
> i decided to fix the ligand molecule during refinement and
> put off pvdw energy function only between the halves of the
> ligand molecule.
> that should effectively lower my Rf and Rcryst values , shouldn'it ?
> but my refinement seems to follow to similar Rf and Rcryst with or without
> pvdw function put to zero.
> i am using CNS at present,
> Any suggestions regarding fixing the problem in either CNS or CCP4 are
> thanx everybody!
> Goel M.