Hi Jorge,
I imagine your 222 tetramer makes a sort of 'pancake' which fits into a
cell of 229x229x36 when you apply the 6-fold symmetry. If that was the
case in the crystal, then these would be the cell dimensions that you
would get.
But I suspect you have a situation where the cell repeat has a
Hi Jorge,
The strong h, k, l=2n and weak h, k, l=2n+1 pattern suggest pseudo body
centering. Does the off-origin Patterson peak lie at/near 0.5 0.5 0.5?
You could get pseudo body centering if an NCS 2-fold lies parallel to a
crystallographic 2(1) or 6(3) screw axis, with the NCS 2-fold a quar
I think if there had been a case of a protein quasicrystal, it would have made
the cover of Nature
Here are some papers about quasicrystals:
1: Proc Natl Acad Sci U S A. 1996 Dec 10;93(25):14267-70.
New perspectives on forbidden symmetries, quasicrystals, and Penrose
tilings.
Stein
I believe Wayne Hendrickson's lab has had such a case with a 10-fold
symmetric mollusc hemocyanin crystal. This must have been in the early
90's and to my knowlwedge they were never able to solve the structure
even though it diffracted beyond 2 Anstrom.
I'm not sure if this work has been publi
On possibility for #5, the B factors all dropping to the lower limit
during refinement. If you are including all of your low resolution data
(which you should) but have not used a model for the bulk solvent scattering
of X-rays (which would be bad) then you will observe this result. The
refin
> As a side note, Xtriage
> doesn't think things are twinned as was suggested for one some of the other
> diffraction patterns discussed earlier today.
Hi Todd,
Detection of twinning in the presence of pseudo translations / and or
NCS parallel to the twin law is difficult and using model based
te
Dear all,
I am trying to use the "NCS Edits" in Coot to be able to move a range of
residues from a molecule to the NCS related ones and the command
"(copy-residue-range-from-ncs-master-to others ) is not working.
The fragment that I want to add to the NCS related molecules is at the
N-terminus.
The left-out spots would be the diffuse spots, which I assume were not
indexed/integrated. The
sharp spots were presumably used to solve the structure.
JPK
==Original message text===
On Mon, 27 Aug 2007 11:36:08 am CDT Raji Edayathumangalam wrote:
Very dumb question per
Very dumb question perhaps:
If there were two interpenetrating lattices of slightly different cell
dimensions, would we not
expect that the indexing program would leave out a lot of the spots as
"unpredicted" or "uncovered"?
Could someone clarify with respect to the diffraction pattern that has
Apologies, part of my previous message was missing and part
appeared twice. Here is another try:
Jacob,
Some small molecule crystallographers have specialized in solving and
refining structures that, exactly as you describe it, consist of two
interpenetrating, non-commensurate lattices. The usua
I am still eagerly awaiting a biomacromolecular quasicrystal with a five-fold
symmetric diffraction
pattern. It seems that this is entirely possible, if one gets roughly
Penrose-tile shaped oligomers
somehow. But wow, how would you solve that thing? I guess one would have to
modify software fr
Some small molecule crystallographers have specialized in solving and
refining structures that, exactly as you describe it, consist of two (or
more) interpenetrating, non-commensurable lattices. The usual approach is
to decribe the crystal in up to six dimensional space. The programs SAINT
and
What a beautiful and interesting diffraction pattern!
To me, it seems that there is a blurred set of spots with different cell
dimensions, although
nearly the same, underlying the ordered diffraction pattern. A possible
interpretation occurred to
me, that the ordered part of the crystal is suppo
You said:
> 8) Processed in P6, P312 and P321, all of course suggest twinning.
These will all suggest partial twinning, but not necessarily perfect
twinning. I would start to consider twinning a possibility if the
statistics for these lower symmetry space groups suggest a partial twin fraction
of
Dear all,
Please, maybe you could give some suggestions to the problem below.
1) Images show smeared spots, but xds did a good job integrating them. The
cell is 229, 229, 72, trigonal, and we see alternating strong and weak rows
of spots in the images (spots near each other, but rows more sepa
In general, I think we should be careful about too strong statements,
while in general structures with high solvent diffract to low-res,
there are a few examples where they diffract to high res. Obviously,
high solvent content means fewer crystal contacts, but if these few
are very stable?
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