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NCS B-factor differences
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busy with the embo bioinformatics course so this is a tad tardy
>You know, after all these years in xtallography I'm tempted just to point
>out that for anything anyone says, there must be at least 1 counter
>example, and often more like 10 of them.
errrr, i know of at least one case where this is not true ...
but more to the point:
- to 'prove' that the average Bs are real, do the
following: set all B-factors equal to the average
over the complete structure; then refine grouped
Bs in xplor or cns where every group is one of
your six molecules. what you should see is that
the delta B you get is negative for 4 of them and
positive for the other two; in adition, you should
see a clear drop in r and rfree. see:
http://alpha2.bmc.uu.se/gerard/gmrp/gmrp.html
(search for "P2" in that page; the first
occurrence is in the paragraph that discusses
the exact same problem we had with P2 myelin protein
- if you have an experimental map, you can also find
out if or show that your molecules have different
average Bs by comparing the densities for the
various copies with the program SPANCSI (part
of RAVE; manual lives at:
http://alpha2.bmc.uu.se/usf/spancsi_man.html )
hope this helps
--cd