Carl Soja wrote:
Dear all
I tried to solve one structure by ccp4i molrep(resolution at 3.0 A,
space group C222, sequence ID 30%). I can get a good Rfactor 0.528 at
first translation function. However, the second translation function
Rfac is 0.526, the third is 0.525, the fourth is 0.525. All of
the translation function Rfacs are too closed. I changed the model
and minimum resolution for search, the Rfactor closed no any improved.
My structure estmates four molecules in the aymmetric unit. This is
my first time found the closed Rfac by molrep. From the low
translation function Rfac, it seems that it is correct solution. I
checked the solution and found some clashes in the structure.I am not
sure why the Rfactor too closed in next the molecule search? I know
this is unusual solution by molrep. Does it mean the diffraction data
has problem?
Any suggestions are welcome.Thank you in advance!
Carl soja
To be honest, I would try both Phaser and EPMR (now Open-EPMR) first to
do MR. Both especially excel at finding good MR solutions for multimers,
and are very fast as well. These programs can find solutions that are
very difficult to find using other rotation-translation programs,
including MOLREP. In my experience (using Phaser and EPMR) reasonable MR
solutions almost always have an R-factor under 50%.
Cheers,
--
------------------------------------------------------------------------
Roger S. Rowlett
Professor
Colgate University Presidential Scholar
Department of Chemistry
Colgate University
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