Yes, in principle, on paper it is possible. Moreover in many cases by looking
at the various directional Wilson plots you may be able to see direction of
helices (just like in DNA/RNA). However in general case it is a little bit
tricky (mixture of different secondary structures directed in diffe
It seems to me that spherical forms of Wilson plots could be used to
determine how many bonds of what nature were oriented in which direction,
and this may have been what Bricogne's micro molecular replacement
technique was capitalizing on? For example, one might be able to orient a
straight DNA mo
As far as I know there are several bumps: around 3.5-4 (there are some at low
resolution related with molecular shapes also) - secondary structures, ~2.2
related with angles and around 1.2 related with covalent bonds. For DNA/RNA
there is one more bump around 1.6-1.7 ( I thought that is because
-BEGIN PGP SIGNED MESSAGE-
Hash: SHA1
Hi Nat,
isn't this partially discussed by Morris' and Bricogne's article about
"Sheldrick's 1.2A rule and beyond" (Acta Cryst D59, 2003)?
Tim
On 05/09/12 20:44, Nat Echols wrote:
> On Wed, May 9, 2012 at 11:35 AM, Edward A. Berry
> wrote:
>> Still
> A protein would only scatter but not diffract
or Diffract but not scatter? isn't diffraction a kind of scattering?
But yes, the atoms in the unit cell may seem random in that
distance range (in fact this is assumed in wilson scattering)
but in a perfect crystal they will be the same in each uni
Beadle Center
1901 Vine Street
Lincoln, NE 68588
(402) 472-3626
mwilso...@unl.edu
Jacob Keller
Sent by: CCP4 bulletin board
05/09/2012 12:22 PM
Please respond to
Jacob Keller
To
CCP4BB@JISCMAIL.AC.UK
cc
Subject
Re: [ccp4bb] Powder Rings in Single Crystals
Yes, I just looked up the
Yes, I just looked up the paper--seems right on topic--a powder-type ring
at ~4.2 Ang, corresponding to Calpha-Calpha distances! But no 1.2-1.5 Ang
ring, from what I saw. Maybe it gets swamped out by other things. I am
thinking that the variety/distribution of bonds/distances of length 1-3 Ang
in t
Dear Jacob,
Our, ie protein, crystals usual diffuse scattering ring involves a
typically 2.8 Angstrom solvent oxygen to oxygen distance.
There must be a 1Angstrom OH diffuse scattering ring but the weakness
of the hydrogen scattering mitigates against that.
The covalent links, to which you refer, a
-BEGIN PGP SIGNED MESSAGE-
Hash: SHA1
Hello Jacob,
I do not know the data, but the word 'fibre' sounds close to
'one-dimensional crystal', especially considering the screw axis you
have in DNA, at least within the resolution limits that the pictures
suggest.
Cheers,
Tim
On 05/09/12 18:3
Well, what about the original DNA fiber diffraction images--no
microcrystals there, as far as I know, but one can clearly see the stacking
distances and the phosphate backbone.
JPK
On Wed, May 9, 2012 at 11:03 AM, Tim Gruene wrote:
> -BEGIN PGP SIGNED MESSAGE-
> Hash: SHA1
>
> Dear Jaco
-BEGIN PGP SIGNED MESSAGE-
Hash: SHA1
Dear Jacob,
A protein would only scatter but not diffract, the latter - in my
understanding - being the result of constructive interference from a
regular array of unit cells .
A powder pattern is the superposition of many small crystals amongst
whic
Dear Crystallographers,
the "saxs on crystals" thread reminded me of a question I have had for a
while, and never having collected data better than ~1.6 Ang or so, cannot
answer myself from experience: I would think that there might be
powder-like diffraction rings at distances corresponding to th
12 matches
Mail list logo
