Well, this is of course just my undereducated two cents but the first
question I'd ask is: asuming that dataset #2 is a real derivative - can I
find realistic sites? What are you basing your resolution cutoff on - in the
diffraction images, do you visually observe anisotropy?
It's not uncommon for derivatives to change diffraction properties of the
crystal anisotropically - for instance if a derivative site happens to be on
a major crystal contact in a specific direction within the crystal.
Can you get better data (better crystals)? It's awfully hard to trace
experimental maps at 4+ A especially if you have no NCS multiples to help
you with crummy phases.
Artem
"Nothing is built on stone; all is built on sand, but we must build as if
the sand were stone"
Jorge Luis Borges
-----Original Message-----
From: CCP4 bulletin board [mailto:[log in to unmask]] On Behalf Of
Francis E Reyes
Sent: Wednesday, August 26, 2009 4:23 PM
To: [log in to unmask]
Subject: [ccp4bb] suggestions for SIR with strong diffraction anisotropy in
the derivative
Hi all
I'm trying SIR on my crystal both are C222.
Native
Cell Dimensions: 97.66 243.45 87.62 90 90 90
Resolution: 4.3
Derivative
Cell Dimensions: 96.9100 244.66 87.61 90 90 90
Resolution: 4.7
. I plan to scale together using FHScal. Ctruncate says that my
derivative has strong diffraction anisotropy. How concerned should I
be about this at the level of phasing? Is there anything to be done
with the anisotropy issue?
Thanks
---------------------------------------------
Francis Reyes M.Sc.
215 UCB
University of Colorado at Boulder
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