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Sounds like it could be a possible twinning issue or a misassignment of space group. SFcheck will give you an idea as to whether you have a twinning problem. J Yi Xue <[EMAIL PROTECTED]> wrote: > *** For details on how to be removed from this list visit the *** > *** CCP4 home page http://www.ccp4.ac.uk *** > > > Hi, all: > I tried to solve a protein structure by molecular replacement. The apo > form is already solved, I crystallized it with Cu(II). The data > diffracted > to 1.6A, the highest resolution shell has more than 80% completeness, R > is > 43%. > I used phaser to find the MR solutin ,then used Refmac to do rigid body > refinement, and restrained refinement. I adjusted weighing factor to keep > chi^2 exactly 0.01. After these steps, R is around 0.30, Rfree is about > 0.37. > Then I fed all the data to arp/warp, it showed that while R decresed, > Rfree increased, and finally, Rfree is around 40%. > I tried to manual build the model, however, I found that most density > were unambigously assigned. I only need to do some small adjustments, > these > minor adjustments did not improve R factors a lot. > All suggestions are highly appreciated. > > Best regards > Yi >
