Well - you can hardly get a higher symmetry space group to match some of
the NC related molecules!
Good luck with the number 6.
This isnt any real help but I cant solve a ferritin structure in SG I432
- it probably forms a cage like the other feritins around the origin,
but every solution I get clashes with others..
After listening to a lecture by a small molecule crystallographer I
wondered whether there isnt some crystal defect but I am not sure how to
monitor it..
Eleanor
Yanming Zhang wrote:
Sorry I forget to tell ya the details:
The SG of my Data is cubic P4332. Cell is 251.34A in all three
dimensions.
Resolution is 3.1A. 5,6,7,8 might be the possible copies from Matthew
coeficient. But I just trust 6 because Chinese like the number 6
(happy Chinese new year by the way :)). No pseudo translation judged
by Native Patterson. Self-rotation at the section kappa=180 shows
strong peaks at phi=45 and psi=45.At the stage of map generation, the
Rfree is 42% R is 38%.
Thanks!
Yanming
On Tue, 13 Feb 2007, Eleanor Dodson wrote:
Sometimes this sort of disorder is due to an error , so the first
thing is to check very carefully that the solution makes sense.
Why are you so sure there are 6 copies in the asymmetric unit?
In situations like this I first worry about SG.
Is there a pseudo-translation vector? This can make it hard to decide
on the SG..
Is there an alternate spacegroup with fewer molecules in the asymm unit?
What does the self rotation show?
Yanming Zhang wrote:
Dear All,
Maybe this is a trivial question:
My data should have 6 molecules in one assymetric unit. MR could
find out 4 molecules. After this, no matter how hard I have tried,
no more molecules can be found. At this stage, I suppose that all
other copies are dis-ordered. And go ahead to do refinement with 4
molecules (ABCD) available.
The density for A is quite good. But for BCD are very dis-ordered.
Many breaks in chains. I'd like to ask you:
In a situation like this, should I:
A, Use NCS for all copies?
B Do not use NCS at all?
C, Use NCS just for BCD? (even dis-ordered, but similar)?
What is the trick to lower down Rfree as soon as possible, if you
have experienced the same situation before?
Thanks
Yanming
