Yuri,
note, the R-factors in case of twinning are not directly comparable.
Pavel
On Thu, Sep 29, 2011 at 7:25 PM, Yuri Pompeu wrote:
> after 1 round of refmac rigid body and restrained refinement with twin law
> (estimated alpha 0.47)
> I am looking at 0.25 -0.29 Rwork Rfree and overall FOM 0.
after 1 round of refmac rigid body and restrained refinement with twin law
(estimated alpha 0.47)
I am looking at 0.25 -0.29 Rwork Rfree and overall FOM 0.72.
I also defined NCS restraints...
I am now realizing that! I have been refining with twin law
enabled, its been somewhat succesful.
I have been using phenix and now
getting ready to try refmac...
regards
On Thu, 29 Sep 2011 15:23:13
+0100, Garib N Murshudov wrote:
> Why do you detwin? It would not be
normal procedure if
I am refining in phenix twin law h,-k,-h-l.
Without twinning I was around 0.36 Rfree and 0.25 with twinning.
I am noticing however that my Rgap keeps increasing slowly... (little
concerned now its at 8% - 0.18-0.26 - to 2.4A)
Maps look decent for 2.4A I have a lot of clashes however some are just
Yuri,
Detwinning relies on having both twin-related reflections present to
calculate either/both of the the de-twinned data values. Therefore it
magnifies incompleteness depending on where your missing data is with
respect to the twin operator.
I'd recommend against trying to do this with a
Why do you detwin? It would not be normal procedure if you have twinning.
Molecular replacement programs usually do not have much problem with twinned
data and refinement programs can deal with them more or less properly.
when you detwin then errors are increased (As far as I remember proportion
After I ran DETWIN with the estimated 0.46 alpha, my completeness for the
detwinned data is now down to 54%!!!
Is this normal behavior? (I am guessing yes since the lower symmetry untwinned
dat is P1 21 1)
You might like to look at this..
It tries to explain likely twinning possibilities in P21.
If you get C and P21, then probably a~=c - then Beta can have any
value.
C222 axes are then always possible with a* +c* , a*-c*, b* all
having angles ~ 90
Without twinning you wont get 222 sy
These papers describe something similar to what I see.
Acta Cryst. (2001). D57, 1829-1835
Acta Cryst. (2009). D65, 388-392
Dear Yuri,
in a monoclinic space group an orthorhombic lattice metric can be
simulated when one of the following conditions is fulfilled:
i) a = c [e.g. in Wittmann & Rudolph (2007) Acta Cryst. D63, 744-749],
ii) the beta angle is close to 90° [e.g. in Larsen et al. (2002) Acta
Cryst. D58, 2055-20
On Tue, Sep 27, 2011 at 11:16 AM, Yuri Pompeu wrote:
> I have a 2.3A data set that could be scaled in C 2 2 21 and P 1 21 1
> Intensity statistics tests indicate twinning (pseudo-merohedral h,-k,-h-l
> in P 1 21 1)
> I find a good MR solution and when I try to refine it with the twin law I
> get
Hello everyone,
I have a 2.3A data set that could be scaled in C 2 2 21 and P 1 21 1
Intensity statistics tests indicate twinning (pseudo-merohedral h,-k,-h-l in P
1 21 1)
I find a good MR solution and when I try to refine it with the twin law I get
fairly good maps and decent Rs 21-28%. I can
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