Dear Sam,
If you have a P1 space group and your dataset was collected in a single
orientation, you will have a great big gaping cusp in it.
I would suggest that you submit your full dataset to the STARANISO
server at
http://staraniso.globalphasing.org/cgi-bin/staraniso.cgi
and take into consideration the distribution of the blue dots. It can be
horrifying: for instance, take a look at
http://staraniso.globalphasing.org/cgi-bin/RLViewer_PDB_scroll.cgi?ID=6oa7 .
The rationale for reducing the resolution at which refinement is done
would be to reduce the proportion (and hence impact) of the systematically
missing data in the cusp, as this gets rapidly worse at high resolution.
The real remedy is to collect data again, this time in at least two
orientations that are different enough to fill each other's cusps at the
highest resolution. Then you will be able to enjoy the full diffraction
limit (2.0A or better) that your crystal seems willing to give ;-) .
With best wishes,
Gerard.
--
On Fri, Jul 05, 2019 at 09:48:35PM +0800, Sam Tang wrote:
> Dear all
>
> Hello again
>
> Thanks a lot for the numerous input.
>
> I received a dataset which was processed to 2.4A but refined to 3A -- this
> was the background I raised this question in the first place. Then I looked
> at the aimless statistics. At 2.4A the high resolution bin CC1/2 0.626,
> I/sigI 2.0, Completeness 84.6, Multiplicity 1.7 (P1 spacegroup). I suspect
> the reason for the refinement resolution limit to be set at 3 A was simply
> due to better Rw/Rf (0.236/0.294 at 3A; 0.284/0.341 at 2.4A).
>
> Based on these information am I justified to say that data quality at 2.4 A
> was suboptimal? In this case do you think refining at a (much) lower
> resolution is acceptable?
>
> Best regards
>
> Sam
>
> On Fri, 5 Jul 2019 at 13:43, Sam Tang <samtys0...@gmail.com> wrote:
>
> > Hello everyone
> >
> > Sorry for a naive question. Is there any circumstances where one may wish
> > to refine to a lower resolution? For example if one has a dataset processed
> > to 2 A, is there any good reasons for he/she to refine to only, say 2.5 A?
> >
> > Thanks!
> >
> > Sam Tang
> >
>
> ########################################################################
>
> To unsubscribe from the CCP4BB list, click the following link:
> https://www.jiscmail.ac.uk/cgi-bin/webadmin?SUBED1=CCP4BB&A=1
########################################################################
To unsubscribe from the CCP4BB list, click the following link:
https://www.jiscmail.ac.uk/cgi-bin/webadmin?SUBED1=CCP4BB&A=1
