> Bottom line: thin shells are not a perfect solution, but if NCS is
> present, choosing the free set randomly is *never* a better choice,
> and almost always significantly worse.
hmmm ... I wonder if that is true. For low order NCS (two- three-
fold, even five-fold) I don't believe that thin shells are better,
since they are a systematic omission of data (whcih can affect maps)
and in my experience they do not add much. I have only limited
experience on this but I somehow tried both and I seem to have
settled with random Rfree. With an NCS axis parallel to a
crystallographic one (or when translation NCS is there) that might be
a whole different ball game though ... not sure.
A.
> Together with multicopy refinement, randomly chosen test sets were
> almost certainly a major contributor to the spuriously good Rfree
> values associated with the retracted MsbA and EmrE structures.
ehm ... I think 16 models systematically displaced along a direction
parallel to helix axes contributed much more to that ... as the
authors basically said in the original publication if my recollection
is not bad.
A.
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