Hi Ming, Just to share an experience: I did a MR with NMR model using Phaser (which is I guess the backbone in phenix autoMR) where the identity was close to 100 % and had a similar situation. The Z score was about 4 and it did not look like fitting to the density. The only positive thing was that the cell dimensions and symmetry looked right. That might be the first thing to check. Then displayed the whole molecule in coot and did a real space fitting. That made one hell of a change. The trick is, if you do the real space fitting on a small area, you see what is the script that is running, copy that and run the script changing the amino acid numbers (i.e, taking the whole thing, 1-n). For the multidomain case, are you sure that there is no funny clash? The solution might look much worse in that case. It just might be worth to try combinations of two domanins, not three, for example, domain A and C. Best, Partha On Dec 3, 2007 6:47 AM, ming lu wrote:

Hi everyones

I am trying automr to solve the structure of my protein. It has three domains, each domain has NMR structure available. So the sequence identity of my search model is 100%. I tried use mutiple components as search models, but I had a hard time to obtain a interpretable solution. Any suggestions on the use of mutiple components as search models? or suggestions on how to use NMR structure as search models? Thanks for your help.

Ming

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Hi, We've had reasonable success with NMR ensembles. A couple of suggestions for things to try: 1. We don't usually find that it helps to include more than the first 5 or so members of the NMR ensemble. 2. Even if the sequence identity is 100%, NMR structures usually aren't as good as X-ray structures for molecular replacement models. So rather than letting Phaser choose an RMSD for the model from the sequence identity, I usually set the RMSD to 1.5A for NMR models. Let me know if you're still having trouble. Randy Read On Dec 3 2007, ming lu wrote:

Hi everyones

I am trying automr to solve the structure of my protein. It has three domains, each domain has NMR structure available. So the sequence identity of my search model is 100%. I tried use mutiple components as search models, but I had a hard time to obtain a interpretable solution. Any suggestions on the use of mutiple components as search models? or suggestions on how to use NMR structure as search models? Thanks for your help.

Ming