On 4/10/2012 10:44 PM, Kay Diederichs wrote:
Hi Dale,
my experience is that high-B regions may become "visible" in maps only late in
refinement. So my answer to the original poster would be - "both global reciprocal-space
(phase quality) and local real-space (high mobility) features contribute to a region not appearing
ordered in the map". This would be supported by your experience if those residues that you
could not model in 3BCL had high (or at least higher) B-factors compared to the rest of the model.
Is that so?
Actually the residues I couldn't model in 3BCL had no B's... :)
Seriously, the residues that appeared for 4BCL did have B values much
higher than average. Their density was weak in the best of circumstances
and more susceptible to obliteration by the distortions caused by
imprecision in the phases. I don't really want to describe this as "phase
error" as that phrase conjures notions of large changes in phase. The
R value only dropped from 18.9% to 17.8% from 3BCL to 4BCL. I don't
expect there were huge differences in the phase angles, but the differences
were enough.
Dale
best,
Kay
