Hi Mani,
Yes: maps should have higher than 10A resolution for automated B-factor
correction. The reason why is explained in Rosenthal&Henderson 2003:
from 10A onwards the Guinier plot of molecules becomes flat, which is
what we use for finding the B-factor. If you have less than 10A
resolution, than you should use the --adhoc_bfac to sharpen your map.
However, at 18A resolution, sharpening will probably not make such a big
difference...
HTH,
S
On 10/25/2013 10:54 AM, Manikandan KARUPPASAMY wrote:
> Hi Sjors,
>
> Please ignore the previous incomplete email.
>
> I would like to know why we are not getting any estimation of B-factor.
>
> ******
> == Fitting straight line through Guinier plot to find B-factor ...
> + fit from resolution: 10
> + fit until resolution: 0
> + slope of fit: -nan
> + intercept of fit: -nan
> + correlation of fit: -nan
> == Low-pass filtering final map ...
> + filter frequency: 16.1418
> ******
>
> I run the postprocess as follows
>
> $relion_postprocess --i Refine3D/run1_ct13 --o
> Refine3D/postprocess_run1 --angpix 5.79 --auto_mask --auto_bfac
>
>
> Do maps should have resolution higher than (<) 10 A for the B-factor
> estimation?
>
> The current resolution of the map is about 18 A.
>
> with kind regards
>
> Mani.
--
Sjors Scheres
MRC Laboratory of Molecular Biology
Francis Crick Avenue, Cambridge Biomedical Campus
Cambridge CB2 0QH, U.K.
tel: +44 (0)1223 267061
http://www2.mrc-lmb.cam.ac.uk/groups/scheres
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