Hi Sadaf,
Most likely you are dealing with radiation damage. If that's the case, you
would need to refine occupancies as Mario has already suggested. However, you
may not find a double conformation. Instead, you may find that some of your
sulfurs are "gone".
There is a ton of publications on th
Since small molecules are being discussed maybe I should comment. A widely
used small molecule program that I don't need to advertise here refines
against all measured intensities unless the user has imposed a resolution
cutoff. It prints R values for all data and for I>2sig(I) [F>4sig(F)].
The
Yes, I would classify anything with I/sigmaI < 3 as "weak". And yes, of
course it is possible to get "weak" spots from small molecule crystals.
After all, there is no spot so "strong" that it cannot be defeated by a
sufficient amount of background! I just meant that, relatively
speaking, the
Could you please expand on your statement that "small-molecule data has essentially no weak
spots."? The small molecule data sets I've worked with have had large numbers of "unobserved"
reflections where I used 2 sigma(I) cutoffs (maybe 15-30% of the reflections). Would you consider those
"we
Hi Sadaf,
You may want to try to play with the occupancy. I have had a case before
where the disulfide bond had double occupancy. In my case it was obvious
because I could see the other density, but sometimes you can just see a
major one due to disorder.
I hope that helps,
Mario Sanches
On Sun,
I should probably admit that I might be indirectly responsible for the
resurgence of this I/sigma > 3 idea, but I never intended this in the
way described by the original poster's reviewer!
What I have been trying to encourage people to do is calculate R factors
using only hkls for which the s
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