Hello Niu,
1. We need extra information. What program did you use ? What's the
similarity (e.g. % identity) of your model. What's your space group ?
Did you try ALL the space groups in your point group in ALL the
permutations (e.g. in primitive orthorhombic there are 8 possibilities).
1a. My best guess on limited info is that you've got a partial solution
in the wrong space group with only part of the molecules at their
correct position.
2. I recently had a very unusual case where I could solve a structure
in EITHER P41212 or P43212 with similar statistics, but that I would see
interpenetrating electron density for a second, partial occupancy
molecule no matter which of these space groups I tried (and it showed
this when I expanded the data to P1). Might conceivably be a 2:1
enantiomorphic twin, in retrospect, but we obtained a more friendly
crystal form. I hope you don't have something like that, but it's possible.
Phil Jeffrey
Princeton
On 11/14/13 5:22 PM, Niu Tou wrote:
Dear All,
I have a strange MR case which do not know how to interpret, I wonder if
any one had similar experiences.
The output model does not fit into the map at all, as shown in picture
1, however the map still looks good in part regions. From picture 2 we
can see even clear alpha helix. I guess this could not be due to some
random density, and I have tried to do MR with a irrelevant model
without producing such kind of regular secondary structure.
This data has a long c axis, and in most parts the density are still not
interpretable. I do not know if this is a good starting point. Could any
one give some suggestions? Many thanks!
Best,
Niu
