I know this question has been answered and Dirk has waved off further
discussion but... I have an answer from a different than usual perspective
that I've been dieing to try out on someone.
Assume you have a one dimensional crystal with a 10 Angstrom repeat.
Someone has told you the value
We see BME adducts in all of our estrogen receptor structures, though we don't
always put them in the models. Sometimes we only see one or two atoms of the
adduct, and in others it is completely ordered. We only see it on the solvent
accessible cysteines. We do it on purpose. We used to treat th
I've seen BME adducts many times both in structures and via MS. DTT adducts
are somewhat less common (due to intramolecular disproportionation into
oxidized DTT and free SH) but still observable:
http://www.ncbi.nlm.nih.gov/pubmed/11684092
So - not only is this possible, but practically commonpla
For some reason this news affects me deeply. I did not know Bill Lipscomb well,
but I interacted closely with James when he was in the UNC Computer Science
Department long ago, and members of the Colonel's scientific family have
impacted me positively any number of times. So, I share the sorrow
We had a case with a BME adduct clearly seen in the structure.
PDB ID 1CY5.
Leemor
On 4/15/11 4:09 PM, "Michael Thompson" wrote:
> Hi All,
>
> I was wondering if anyone knew whether or not it is possible for reducing
> agents with thiol groups, such as DTT or beta-mercaptoethanol (BME), to fo
Hi All,
I was wondering if anyone knew whether or not it is possible for reducing
agents with thiol groups, such as DTT or beta-mercaptoethanol (BME), to form
covalent S-S bonds with Cys residues, particularly solvent-exposed Cys? I have
some puzzling biochemical results, and in the absence of
Nobel Laureate William Lipscomb Dies at 91
By THE ASSOCIATED PRESS
Published: April 15, 2011 at 2:01 PM ET
I have had this forwarded to me, besides getting a Nobel prize for his
discovery of the bent bonds in boron hydrides, the Colonel was a pioneer in
PX, with work on the role of Zn in carboxyp
Hi Robert,
If you don't mind the crystals being rather small, then polyhedra crystals
might be what you're after (in fact, many microcrystals satisfy your
criteria). There is a mini review here:
http://dx.doi.org/10.1080/0889311X.2010.527964
These articles should also help.
Ji, X.; Sutton, G.; E
Dear Gregory,
You need a sufficient number "n" of free reflections to get a
statistically valid Rfree value. 500 should be ok. I normally select 5%
free reflections. However, I always hate it when programs decide that
they know better than the user. Nobody prevents you from using your
original mt
Dirk
Another way of looking at it
See slide 7 in
http://www.aps.anl.gov/Science/Future/Workshops/Frontier_Science_Using_Soft_Xrays/Presentations/WeierstalTalk.pdf
sampling interval 1/W (Bragg sampling) is Shannon sampling if complex
Fraunhofer wavefield of object with width W is recorded.
If o
My name is Greg Costakes and I am a graduate student for Cynthia Stauffacher at
Purdue University. I am attempting to solve the structure of an 18kDa protein
domain using molecular replacement to obtain proper phasing (44% identical /
78% homologous to an existing structure). Crystals diffracted
Hi Dirk,
My interpretation of your question is what is the impact of resolution given
by the individual diffraction spots from the electron density sampling and
the Nyquist theorem. My explanation would be that the Nyquist theorem gives
an upper limit to the frequency information that can be obtai
Dear colleagues of the CCP4BB,
many thanks for all your replies - I really got lost in the trees (or
wood?) and you helped me out with all your kind responses!
I should really leave for the weekend ...
Have a nice weekend, too!
Best regards,
Dirk.
Am 15.04.11 13:20, schrieb Dirk Kostrewa:
Dear Dirk,
You are getting confused about where the sampling occurs, and this is
perhaps because we usually learn about the Shannon criterion from a
certain way around (sampling in real/time space -> periodicity of the
signal transform in frequency/reciprocal space). To see the Shannon
criterion in
Dear Dirk,
The factor of 2 comes from the fact that the diameter of a sphere is
twice its radius. The radius of the limiting sphere for data to a certain
resolution in reciprocal space is d_star_max. If you sample the electron
density at points distant by delta from each other, you periodise
Dear Ian,
oh, yes, thank you - you are absolutely right! I really confused the
sampling of the molecular transform with the sampling of the electron
density in the unit cell! Sometimes I don't see the wood for the trees!
Let me then shift my question from the sampling of the molecular
transf
Hi Dirk,
If you have a N points of a 1D real discrete function, there will be Fourier
coefficients indexed h=0,1,2,...,N-1. Taking N as odd, there will be
int(N/2)+1 independent Fourier coefficients but your h(max) will in fact
be 'N-1'. In crystallography we write h(N-1) as h(-1) etc and ten
Is the simplest answer that we indeed do not get all of the
information, and are accordingly missing phases? My understanding is
that if we were able to sample with higher frequency, we could get
phases too. For example, a lone protein in a huge unit cell would
enable phase determination. Taken fur
Hi Dirk
I think you're confusing the sampling of the molecular transform with
the sampling of the electron density. You say "In the 1-dimensional
crystal, we sample the continuous molecular transform at discrete
reciprocal lattice points according to the von Laue condition, S*a =
h". In fact the
Dear colleagues,
I just stumbled across a simple question and a seeming paradox for me in
crystallography, that puzzles me. Maybe, it is also interesting for you.
The simple question is: is the discrete sampling of the continuous
molecular Fourier transform imposed by the crystal lattice suff
Hi Gerard
Sorry - what Royal Wedding?
On 15 Apr 2011, at 11:48, Gerard Bricogne wrote:
> Dear Harry,
>
> Thank you for the reminder. Upon connecting to the URL given in
> Martin's e-mail, however, one immediately gets a pop-up saying:
>
> "New deadline fo abstract submission:
Dear Gerard,
you are right, the abstract submission has been extended.
Best regards,
Maria
Quoting Gerard Bricogne:
> Dear Harry,
>
> Thank you for the reminder. Upon connecting to the URL given in
> Martin's e-mail, however, one immediately gets a pop-up saying:
>
>
Dear Harry,
Thank you for the reminder. Upon connecting to the URL given in
Martin's e-mail, however, one immediately gets a pop-up saying:
"New deadline fo abstract submission: April 28"
(no doubt to enable everyone to work until the last minute prior to the
royal wedding ..
Hi folks
today is the last day to get your abstract in!
On 7 Apr 2011, at 14:24, Martin M. Ripoll wrote:
> Dear colleagues,
>
> This is just to remind you that the “XXII Congress and General Assembly” of
> the IUCr (International Union of Crystallography) will be held in Madrid
> (Spain) fro
24 matches
Mail list logo
