ni hao,
I have a question about how to improve the electron density. I have two
indepedent molecules in the asymmetric unit (1.9 A resolution). I solved the
structure with PHASER and refined with CCP4i (Rfree = 0.29).
For the first molecule, the density is very good, but for the second one,
the density is much worse than the first one. Are there any ways to improve
the density of the second molecule, such as some kinds of averaging? Why
that happens?
there can be various causes for this such as undetected twinning or a
spacegroup error. if you can exclude those possibilities, it could also be
that the weak-density molecule has fewer packing interactions and thus is less
well ordered, and therefore has a higher overall temperature factor. you can
investigate this with SPANCSI (http://xray.bmc.uu.se/usf/spancsi_man.html#H5).
--dvd
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Gerard J. Kleywegt
[Research Fellow of the Royal Swedish Academy of Sciences]
Dept. of Cell & Molecular Biology University of Uppsala
Biomedical Centre Box 596
SE-751 24 Uppsala SWEDEN
http://xray.bmc.uu.se/gerard/ mailto:[EMAIL PROTECTED]
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