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[ccp4bb]: Anomalous data in refinement

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Dear All :

I know from browsing through my CCP4 archive that some the
following has been discussed in some form before, but let
me ask again:

Fact: I inherited a Cu dataset of a cytochrome c' at 1.8 A. I got
it Friedel merged, rsym=10%. Estimated anomalous contribution ~2%
Common wisdom has it that - at least at such a modest resolution - the
anomalous differences in f get gobbled up in B. At higher res,
programs like SHELXL can be coerced into dealing with it, and the
reward is at least a proper Flack parameter.
I also remember reading on board that a better redundancy by merging
might as well compensate for the possible improvement in considering
anomalous contributions in refinement (I am not so sure...).

Is this true? Does anyone have actual experimental evidence for my
above assumptions? Can REFMAC deal with anomalous refinement?

The refinement converged at freeR 26.2 and R =22.0, with nearly
perfect looking bias-minimized warp maps (<CC>=92)and good geometry.
I suspect perhaps other merging problems (I don't have the
original frames yet). And yes, I can
throw waters in until I get freeR=27 and R=19.9........

I also notice that HGEN cannot generate H's for heme (protoporhyrin)
(admittedly I still use refmac 4). I suppose HGEN will become
unnecessary with the new libraries used in refmac 5. Along these
lines, while RTFM,

is dead, it is
called from
there are a few more dead links in this page.

Respectfully, br

Btw when is the next official CCP4 release due?

Bernhard Rupp
Macromolecular Crystallography and Structural Genomics
LLNL-BBRP L448                               Phone (925) 423-3273
University of California                     Phax  (925) 424-3130
Livermore, CA 94551                          email    br@llnl.gov
URL                                 http://www-structure.llnl.gov
TB Structural Genomics Consortium  http://www.doe-mbi.ucla.edu/TB
EU Mirror  http://www.dl.ac.uk/CCP/CCP14/ccp/web-mirrors/llnlrupp