[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [ccp4bb]: aniso scal



***  For details on how to be removed from this list visit the  ***
***    CCP4 home page http://www.dl.ac.uk/CCP/CCP4/main.html    ***

Joe Brunzelle wrote:

> ***  For details on how to be removed from this list visit the  ***
> ***    CCP4 home page http://www.dl.ac.uk/CCP/CCP4/main.html    ***
>
> Hello,
>     This question pertains to refmac and aniso scaling.  How do you turn
> off aniso scaling?  I want to do to eliminate contributions from Ucryst (
> Uoverall = Ucryst + Utls + Utorsion + Uatom); if I'm not mistaken shelx
> doesn't do a Ucryst correction.  I have been working a 1.1A refinement in
> both refmac and shelx and when I do an ortep drawing of the molecule from
> the two different programs, the shelx ADPs result in a more elliptical
> shape when compared to the refmac refine model.  I've altered the Bfac
> parameters in refmac but I'm not seeing any significant changes to the
> ADPs.
>  Has anybody looked at how the bfac params compare to simu values in
> shelx? Also, in some of the refmac examples there is reference to allow
> the geometry to be relaxed for hi res. struc. (i.e. weight matrix 40/50).
> What types of geo. values are being reported for these relaxed weights?
>
> Thank you in advance

To turn off aniso scaling you give

SCALE LSSCale ISOTropic

Then program should turn off aniso scaling

One more reason for smaller ellipticity could be SPHEricity restraint. You can relax

it using

SPHEricity <value>

Larger value means less spehericity. Default is 2. I use usually 5.

WEIGHT keyword concerns thermal and positional parameters.

Regards

Garib

--
------------------------------------------------------------------
Garib N. Murshudov, Chemistry Department, University of York, U.K.
Tel: Home +44 (1904) 42 62 87, work:  +44 (1904) 43 25 65
------------------------------------------------------------------