Dear All,
I'm refining an X-ray structure to 1.6A resolution in BUSTER-TNT v2.10.
The model is pretty much finished but I see a strange electron density
that I can't imagine what it is.
Please take a look at four snapshots in
http://www.itqb.unl.pt/~jbrito/ITQB/ . Any pointers/guesses are most
welcome.
In short, I see an oblong piece of density coming straight out of the
main-chain!! It doesn't refine as a "chain" of waters and any small
piece of PEG doesn't refine properly either (actually, not sure if this
would make any sense but since the crystallization condition is PEG3350
and gave it a try!!).
The crystallization condition is PEG3350, Bis.Tris buffer, (NH4)2SO4 and
NaI. The protein was purified from recombinant expression in E. coli
with "trivial" reagents: Tris and Bis.Tris buffers, NaCl, glycerol, ...
Wishing you all an excellent weekend, best regards,
Jose
--
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* José Artur Brito, PhD *
* *
* Post-Doctoral Fellow *
* Membrane Protein Crystallography Lab *
* Instituto de Tecnologia Química e Biológica *
* Oeiras - Portugal *
* *
* Tel.: +351.21.446.97.61 *
* Fax: +351.21.443.36.44 *
* *
* E-mail: jbr...@itqb.unl.pt *
* URL: http://mx.itqb.unl.pt *
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