Dear all,
I am blessed/tormented with a 0.8 A data set for a small protein. I
first refined it using COOT/REFMAC5 until I deemed it done, which meant
manually adding quite a few water molecules that were weak and a little
more distant to the protein. R is 10.2%, R-free is 10.8%.
I realize th
On 13:16 Wed 11 Nov , Matthias Zebisch wrote:
> What is the optimal wavelength for Sulfur SAD phasing?
> Is it 1.9A or should one go below that to reduce absorption/damage.
Some additional advice about factors other than wavelength: For S-SAD on
a home Cu source, my previous lab showed that o
Matthias Zebisch wrote:
Dear bb!
What is the optimal wavelength for Sulfur SAD phasing?
Is it 1.9A or should one go below that to reduce absorption/damage.
Also, would the same wavelength be appropriate to maximize anomalous
scattering to position chlorides, calcium, sulfate in already phased
I played around with a few years back - tried all kinds of different
data collection strategies and wavelengths.
What worked for me was collecting data at wavelength of 1.7A from a
few different crystals and then merge them together to get a higher
redundancy.
Both calcium and sulfur signals
This is very easy to do using SHELXC/D/E, with or without the hkl2map GUI.
All you need are two .sca file, if necessary they can be generated from
.mtz using Tim Gruene's mtz2sca (also available from the SHELX download
site). No special scaling or merging is required.
George
Prof. George M. Shel
Hello,
I am currently working on a problem by SIRAS. I have a native and an
isomorphous SeMet dataset. I have been trying to use SOLVE/RESOLVE by
modifying the MIR file. The problem I am having is with the input file. Can
two separate files be used as input, one native.mtz(scaled amplitudes) and
a
Hi Matthias,
S-SAD seems to require really strong diffraction, high symmetry, and
high data redundancy. In the end, the S ano signal is pretty weak even
at longer wavelength. While S-SAD might work, Iodide soaks might be a
much more practical approach. Iodide has some 6 electrons at CuKa.
.
2.29 Angstrom is an excellent wavelength for Cl, Ca and S anomalous
scatterers. This is the wavelength produced by a Cr home source.
Some older references:
Acta Crystallogr D Biol Crystallogr. 2003 Nov;59(Pt 11):1943-57. Epub 2003
Oct 23. Away from the edge: SAD phasing from the sulfur anomalous
Le 11 nov. 09 à 14:26, Jürgen Bosch a écrit :
Dear CCP4 community,
(hijacking the thread)
I so far failed to get a sulfur SAD phased structure and I blamed it
on the low symmetry space group C2 plus weakish diffraction if you
don't want to overexpose your crystal and be able to collect 20-30
Miguel Ortiz Lombardia wrote:
Of course, as Fred said, the precission of the measurements is
extremely important for sulfur-SAD phasing.
What I was really meaning is the combination of i) accuracy and ii)
sufficient redundancy. Not too much, in your case, as you rightly say in
your mail.
Fred
Hi Matthias
Another crucial point to phase with sulphur anomalous signal is to use
an appropriate scaling protocol. You can find extense discussion in
the reference Matt posted.
In case you want just to calculate an anomalous difference Fourier map
you don't need to go that soft, you can
Dear CCP4 community,
(hijacking the thread)
I so far failed to get a sulfur SAD phased structure and I blamed it
on the low symmetry space group C2 plus weakish diffraction if you
don't want to overexpose your crystal and be able to collect 20-30x
redundancy.
What do the expert think about f
Le 11 nov. 09 à 13:16, Matthias Zebisch a écrit :
Dear bb!
What is the optimal wavelength for Sulfur SAD phasing?
Is it 1.9A or should one go below that to reduce absorption/damage.
Also, would the same wavelength be appropriate to maximize anomalous
scattering to position chlorides, calcium,
Matthias Zebisch wrote:
Dear bb!
What is the optimal wavelength for Sulfur SAD phasing?
Is it 1.9A or should one go below that to reduce absorption/damage.
Also, would the same wavelength be appropriate to maximize anomalous
scattering to position chlorides, calcium, sulfate in already phased
Hi Mattias,
For maximizing the anomalous scattering of chlorides, calcium and
sulfate I always collect highly redundant data (say 7 fold) at 7keV
(1.77A). As for the optimal wavelength for S-SAD I would point you to
the following publication:
http://journals.iucr.org/d/issues/2005/09/00/d
Dear bb!
What is the optimal wavelength for Sulfur SAD phasing?
Is it 1.9A or should one go below that to reduce absorption/damage.
Also, would the same wavelength be appropriate to maximize anomalous
scattering to position chlorides, calcium, sulfate in already phased
structures?
Thanks in a
The Humboldt-University Berlin (HU-Berlin) is looking for a
Postdoctoral Research Assistant for Macromolecular Structure and
Interaction to support the operation of the MX-beamlines located at the
BESSY II storage ring (headed by Dr. Uwe Müller, BESSY/HZB) and to
conduct research at the HU-Berlin
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Nice link.
Thanks
Anthony
-
Dr. Anthony Addlagatta
Scien
Dear all,
Thought I'd share this with you:
I located this through Ms Ines Kahlaoui, from the Beja Higher Institute
of Biotechnology in Tunisia (Ines has to teach and locates videos on the
internet, which she then downloads and uses for teaching). Ines located
this jewel:
http://video.google
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