Without knowing the structure it is hard to make any comment.
Usually the only way to get an R value this low at 3.9 A resolution is
to start with a high resolution model and MR it into the low resolution
map.
It is a good sign for the future of methods development that a good
model will fit a low resolution data set but we don't know how to CREATE
such a good model using ONLY the low resolution data set.
Dale Tronrud
On 3/15/2016 6:36 AM, Smith Liu wrote:
> Thanks Eugene.
>
> The paper I read was from a top journal. The resolution was 3.9, and the
> R-factor was 0.233. I was interested to know how to get Rfactor 0.233
> from 3.9 A resolution map.
>
> Smith
>
>
>
> ÔÚ 2016-03-15 19:42:48£¬"Eugene Osipov" <[log in to unmask]> дµÀ£º
>
> Dear Smith,
> R-factors not the aim but indicators. My teacher taught me that with
> correct weighting scheme rmsd of bonds and angles in your model
> should be similar to rmsd's of monomers in library. So I try to keep
> weight which gives rmsd of bonds ~0.02 after refinement. Focus
> rather on correct description of your model in terms of chemical and
> physical sense.
>
> 2016-03-15 10:57 GMT+03:00 Smith Liu <[log in to unmask]
> <mailto:[log in to unmask]>>:
>
> Dear All,
>
> I just read a sentence " To prevent over-refinement, an
> appropriate weighting of the geometry versus the
> crystallographic term was established empirically, aiming
> at good model geometry with a low R value". By CCP4 refmac
> refine, will you please let me know which strategy are helpful
> for getting lower R value?
>
> Smith
>
>
>
>
>
>
>
> --
> Eugene Osipov
> Junior Research Scientist
> Laboratory of Enzyme Engineering
> A.N. Bach Institute of Biochemistry
> Russian Academy of Sciences
> Leninsky pr. 33, 119071 Moscow, Russia
> e-mail: [log in to unmask] <mailto:[log in to unmask]>
>
>
>
>
>
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