[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: Amore correlation coefficients
*** For details on how to be removed from this list visit the ***
*** CCP4 home page http://www.dl.ac.uk/CCP/CCP4/main.html ***
If you calculate the correlation between Fobs and Fcalc you will always
get a positive outcome because they are correlated in the sense that both
decrease with resolution. If you use E values you do not see this since E
values do not decrease with resolution, as you noted. In your case the
effects may have been more severe, perhaps due to too large B-values for
the search model?
On Wed, 29 Sep 1999, Stephen Soisson 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 ***
> Hi everyone,
> In a recent MR case using Amore, I noticed the following phenomena:
> Using my straight reflection data, the correlation coefficients observed
> during rotation and translation steps were relatively high (30%) which
> seems peculiar since I was searching with only 1/4 of the a.u. When I
> put the solutions into the rigid body fitting function in Amore, it
> re-calculates a scale and B-factor for the data, and the STARTING
> correlation coefficients are much lower now, (22%). Meanwhile, the
> fitting step is applying a B-factor of -90 to my data.
> I have used AMore many times in the past, and never seen these sorts of
> Interestingly, if I instead use E's instead of F's, then I see more
> typical behavior. That is, The rotation solution has a CC of 10%,
> translation 15%, and then fitting behaves normally, and the CC goes up
> to 21%.
> Has anyone else observed anything like this, or have any idea what the
> problem (if there is one) might be??
> Thanks in advance for any help,
> Stephen M. Soisson, PhD Lab of Molecular Biophysics
> firstname.lastname@example.org Rockefeller University
> Phone: (212) 327-7915 New York, New York 10021