I am working with a small protein in a relatively high
space group p6322 and have good data to a modest 2.5 A
resolution. During the first rounds of restrained
refinement however the B factors drop to an average of
15 and as low as 2 A^3. This has the effect of
producing large amounts of negative density in the
voids of the structure. I have tried artificially
rasing the b factors and setting a higher low cutoff
but nothing seems to help. I have also chosen each of
the b models of refinement (anisotropic, overall,
etc.) but to no avail.
Any suggestions?
German Gomez
____________________________________________________________________________________Ready for the edge of your seat?
Check out tonight's top picks on Yahoo! TV.
http://tv.yahoo.com/
|