Dear Khoa,
I would lean in the same direction as James, and say that what
you need is not advice about what refinement program to use, but a
question about whether you could collect better data. With an overall
I/sig(I) of 8.3 and an outer-shell value of 0.5, there is just not
enough oomph in your data, and you might essentially be flogging a
dead horse.
A low symmetry like C2 leaves room for a lot of anisotropy, so
you might want to give a try to the server at
http://staraniso.globalphasing.org/cgi-bin/staraniso.cgi
This will probably not rescue your dataset, but it may give you some
indications that perhaps it is anisotropy that is bringing the shell
average of I/sig(I) to as low a value as 0.5, and that there may be
decently strong data to a certain resolution in some directions that
are getting swamped by noisy data in other directions.
With best wishes,
Gerard.
--
On Sat, Jun 17, 2017 at 03:55:15PM -0500, James Phillips wrote:
> I am not happy with an Rmerge of 20%. Also what is the Rmerge and
> redundancy in the highest shell, i.e. do you really have the resolution of
> 2.9?
>
> How did you collect this data? SR or lab.
>
>
>
> James Phillips
>
> On Wed, Jun 14, 2017 at 8:09 AM, Khoa Pham <khoa.p...@einstein.yu.edu>
> wrote:
>
> > Dear CCP4 members,
> >
> > I am refining a structure with a resolution of ~ 2.9 A and the Rwork/Rfree
> > are are 0.34/0.37, respectively.
> > My question is that these Rwork/Rfree are acceptable for publication. If
> > not, how can I reduce them?
> >
> > Thank you.
> >
> > Khoa
> >
> > The table of statics.
> >
> > Space group
> >
> > C121
> >
> >
> > Resolution (Å)
> >
> > 29.69-2.92
> >
> > No of unique reflections
> >
> > 61569 (8747)
> >
> > Rmerge (%)
> >
> > 20 (350)
> >
> > Rpim (%)
> >
> > 11 (198)
> >
> > I/s(I)
> >
> > 8.3 (0.5)
> >
> > CC1/2
> >
> > 0.99 (0.33)
> >
> > CCanomalous
> >
> > N/A
> >
> > Completeness (%)
> >
> > 98.5 (95.8)
> >
> > Redundancy
> >
> > 4.2 (4.0)
> >
> >
> >
> >
> >
> > *Refinement*
> >
> >
> >
> > Resolution (Å)
> >
> > 29.69-2.92
> >
> > No of reflections
> >
> > 58394 (4069)
> >
> > Rwork/Rfree
> >
> > 0.3380/0.3689
> >
> >
> > R.m.s. deviations
> >
> >
> >
> > Bond lengths (Å)
> >
> > 0.0073
> >
> > Bond angles (o)
> >
> > 1.1062
> >
> >
> >
--
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