Dear Phil, I used PHASER to do the task. I have double checked and both files have the same prefix, so they are from the same output. I have also checked the headers again, they have the same spacegroup. Actually I was trying to search for two different molecules but only one was found. The spacegeoup is P2 and I am quite sure it is not P21 from system absence.
One possibility is that the space group was wrong, since there is a 95% off origin peak. There are several choices from data processing, P1, P2, C2 C222, all have this large off origin peak. I wonder if this 95% peak can tell some information? It will not surprise me if this result is incorrect, however how could these regular density be? Best, Niu On Thu, Nov 14, 2013 at 5:47 PM, Phil Jeffrey <pjeff...@princeton.edu>wrote: > 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 >> >> >> >
