Can we have more details?
Do you only have 3.6A data? If so it is quite likely there is a good
deal of real disorder? Or that your MR solution was slightly out for
that molecule.. Could you have the wrong soacegroup - one related to the
one you are using?
Are the two heterodimers related by some special operator - NCS
translation? Possible twinning? This can make it hard to get the
spacegroup right..
In these sort of situations I leave out the offending molecule
altogether and check what you can see in the maps based on the 3 wel
defined molecules. If there is residual density even if broken then
maybe you can start fitting it again.
Eleanor
RONG hui Rong wrote:
Dear all,
I am solving a structure containing 2 heterodimers in one ASM. First, got
the solution by MR( 11-3.6Å, modified model template with Rfac and Rfree 47%
and 48%,respectively). After some model building by hand in terms of
2mFo-DFc map bearing 0.41 for Rfac and 0.42 for Rfree, except molecule 1,2
and 3 fitting the 2mFo-DFc map well , the 4th molecule presenting poor,
however, the 4th molecule fit the mFo map well( of course, another 3 mols
fit well). After model building by hand based on the mFo map coupled with a
cycle of simulating and minimizing, it produced poor maps (2mFo-DFc as well
as mFo, almost main chain broken, disorderly) for mol 4 except molecule 1,2
and 3 fitting the 2mFo-DFc as well as mFo map well and just a little
decreasing on Rfac and Rfree.
How can I do? Can anybody give me some inspiration?
Many Thanks!
SCL
