Dear Eleanor, Thank you very much for your reply. I think that the NCS operator is very close to the crystallographic two fold symmetry because when I searched for the solution with PHASER with one molecule as the model I could not find the solution so I have to use two molecules as the search model but I did not expect that will affect the NCS refinement. How to deal with this problem?
Thank you very much for your great help! I also greatly appreciated all the replies to my question which help me clarify a lot. Thank you All! Best wishes, Sun ________________________________ From: Eleanor Dodson <c...@ysbl.york.ac.uk> To: Sun Tang <suntang2...@yahoo.com> Cc: CCP4BB@jiscmail.ac.uk Sent: Wednesday, July 8, 2009 10:06:41 AM Subject: Re: [ccp4bb] Why NCS doesn't help? There are many reasons why this could have ocurred. One is that your NCS operator is very close to being a crystallographic one. But you need to give more details of the problem before I can comment sensibly Eleanor Sun Tang wrote: > Dear All, > > In refining my structure (two molecules in au) that was solved with molecular > replacement, refinement starting with restrained lowered the R-free to about > 0.35 while with NCS increased the R-free to 0.55. Does it imply that two > molecules are quite different or something wrong with the refinement? > > Thank you very much for your suggestions? > > Best wishes, > > Sun Tang > > > > >