WA(xray)

Tony Planchart planchart at XTAL200.HARVARD.EDU
Fri Sep 20 19:41:48 EST 1996


Hi,

I'm a bit puzzled about the x-ray data weight... I recently computed the
weight for my data set (using 3.1) and set out to test the effect of the 
weight on the free and working R.  These are the results I obtained:

0.5 * WA
  Rfree=31.7%
  Rwork=28.4%

1.0 * WA
  Rfree=31.3%
  Rwork=27.3%

1.5 * WA
  Rfree=31.0%
  Rwork=26.7%

The SA protocol was pretty standard... NCS restraints (200 kcal); Init. temp. 3000;
harmonics (10 kcal), etc.  Data to 2.9 A (range 10 - 2.9).
I don't believe the differences obtained are significant -- though I'm inclined to
go with 1.5*WA although this is contrary to Axel's recommendation.  I'm wondering
if in my case this would make much difference and would like to know if anyone has had
similar experiences, what you've done with the results, etc.  Any advice is gladly
accepted.

Tony

  
______________________________
Antonio Planchart, Ph.D.		
Dept. of Mol. and Cell. Biol.
Harvard University
7 Divinity Avenue
Cambridge, MA 02138
Lab Phone (617) 495-5043
Fax	  (617) 495-9613



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