[sharp-discuss] Simple Q: FP,SIGFP in solvent flattened .mtz

[Clemens Vonrhein]

Hi Francis,

On Tue, Aug 16, 2011 at 11:03:09AM -0600, Francis E Reyes wrote:
> When using FPsha/SIGFPsha, I imagine those are recalculated with
> every SHARP run?

In principle yes.

> i.e. If I refine a model against a set of experimental phases, rerun
> sharp (calculating the phases from the updated model and combining
> them with the new sharp phases), FPsha/SIGFPsha will be different
> from experimental phases used to refine the model ?

Using model phases in a SHARP run changes the complex plane which in
turn changes the FP/SIGFP values. How large would those changes be
however? Often, including model phases (or density-modified phases)
into the SHARP steps helps solving the structure - by stabilising the
refinement and/or pushing the maps over into interpretability. But I
would expect those FP/SIGFP values to change only a little bit.

You could compare those sets by calculating an R-factor between them.
If you have autoPROC installed:

  % check_indexing -v logfiles/run.1/eden.mtz logfiles/run.2/eden.mtz

or by hand using RSTATS from CCP4?

Cheers

Clemens

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