On Sat, 11 Jun 2011, Vellieux Frederic wrote:
If the diffraction pattern originates from 2 crystals (in different
orientations, a case I've had with one large crystal plus a satellite
crystal attached to it in the same loop), it is in principle possible to
<snip>
crystal. I don't think such a modification of the data processing programs
is available.
It is possible to process diffraction spots from both crystals using XDS.
The procedure is described here (under 'Index and integrate
multiple-crystal diffraction'):
http://strucbio.biologie.uni-konstanz.de/xdswiki/index.php/Tips_and_Tricks
-Konstantin
But could you explain more clearly the problem?
Fred.
Marco Lolicato wrote:
Dear all,
I have a particular problem...
so, I have a beautiful crystal with nice diffraction pattern at 2.7A. The
diffraction images are composed by very strong spots and weak spots.
With XDS, if I collect all spots I get good map, but it is impossible to
solve the structure by molecular replacement. If I collect only the
strongest spots (STRONG_PIXEL= 99), I'm able to solve a very good
structure...
My problem is: I was trying to get the apo-structure of my protein. I
obtained nice crystals of the "apo-protein", but using the method above,
in the structure I have found also the ligand!! (probably incorporated
during the overexpression). My protein is a multimer and, biochemically,
I found that the endogenus ligand bond to the protein is in the ratio
1:6. ...and I got a crystal in this way.
So, is there a way to analyze all spots in the diffraction pattern to
have a structure of the apo-protein?
Is a good idea discard the strongest spots and try to analyze only the
weak spots? If yes, how I can do it?
All the best,
Marco
--------------------------
Konstantin Korotkov, Ph.D.
Research Scientist
University of Washington
Department of Biochemistry
Box 357742
Seattle, WA 98195-7742
(206)616-4512
[email protected]
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