Re: solvent correction?

[Edward Berry <eaberry@lbl.gov>]

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S.Ravichandran wrote:
> 
>         I guess the bulk-solvent plays a major role in controlling these
> low-resolution part, as in CNS it is not the same 'Babinet principle'..
> (It uses a solvent-masking procedure....??)..
> 
I presume that refmac also uses a mask, and Babinet only refers to the
fact 
that it calculates for higher density inside the protein mask, then adds
180 
degrees to the phases to invert it (or optimizes a negative coefficient
to
use in combining). The result should be identical if the atomic radius
for 
the mask, the solvent density, and solvent B-factor are the same. 

Since CNS allows one to fix these 3 parameters, it should be possible to
narrow down the contradiction if you can take the values used by refmac,
put them into CNS, and calculate FPART.

(My apologies if this is a gross oversimplification of the process)

Ed Berry