I agree with Errin Merrit - any problem is usually in the data. REFMAC
gives a useful plot of <Fobs> v <Fcalc> - look at that and check that
they both are nice shapely curves,
If there is a glitch at the point you merged the two data sets then you
can either go back and try to process better, or decide that you have a
lovely structure which answers your biological Qs and go on...
the CCP4 GUI developers have put a lot of effort into providing
information about data processing, refinememt etc in a graphical form,
and I fear it isnt always checked as carefully as it should be!!!
Grump
Prem kumar wrote:
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hi,
Thanks for responses i got!
I have already checked the data with sfcheck &
truncate. there is no pseudosymmetry and twinning. for
same protein we did the structure in low resolution.
we didnt face any problem.
cell parametres are 52.588 52.588 47.848 90.00
90.00 90.00 P43
I looking into other aspects peoples suggested me.
regards
prem
--- Peter Zwart <[EMAIL PROTECTED]> wrote:
what is your cell and symmetry?
have you condisered twinning?
Prem kumar wrote:
Hi,
I am refining atomic resolution (0.9 A) structure.
I am facing problem
with R-factor 15.2 and R-free 18.5 even after
anisotropic refinement
(including hydrogen), which is high for atomic
resolution data. the
model seems to be fine and almost every residues
and water fitted well
in electron density. i found few alternate
conformation and included
them for refinement, but still R-factor is not
coming down. I tried
different programs. shelx gives above said values.
refmac gives 17.3
and 19.5. I followed steps mentioned in manual. I
tried Arp/Warp too.
Its able to build only 110 residues out of 121
residues with R-factor
21.0 and R-free 23.4.
data (synchrotron) was collected in two sets, one
for high resolution
and one for low resolution. Rsym - 5.0(55.0),
I/sig I - 17.2(2.0),
completness - 99.8(100).
what are the ot! her factors I need to look into?
Please suggest me how to proceed further.
Thanks in advance!
Regards
R. Prem Kumar
Research Scholar, Deptt. of Biophysics, AIIMS, New
Delhi.
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======================================================
R. Prem kumar
Research Scholar,
Department of Biophysics,
All India Insitute of Medical Sciences(AIIMS),
New Delhi-110029.
INDIA
Phone: +91-11-26593201,26588931
FAX : +91-11-26588663
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