Check for translational NCS And you are way too conservative with resolution. Even those holding onto the Rmerge-dictated past would probably acquiesce to lower I/sig cutoff. If you are using aimless, follow its recommendations based on CC1/2, it's good for you.
Cheers, Ed. On Fri, 2013-03-15 at 15:39 -0300, Andrey Nascimento wrote: > Dear all, > > I have collected a good quality dataset of a protein with 64% of > solvent in P 2 21 21 space group at 1.7A resolution with good > statistical parameters (values for last shell: Rmerge=0.202; > I/Isig.=4.4; Complet.=93% Redun.=2.4, the overall values are better > than last shell). The structure solution with molecular replacement > goes well, the map quality at the protein chain is very good, but in > the final of refinement, after addition of a lot of waters and other > solvent molecules, TLS refinement, etc. ... the Rfree is a quite high > yet, considering this resolution (1.77A).(Rfree= 0.29966 and Rfactor= > 0.25534). Moreover, I reprocess the data in a lower symmetry space > group (P21), but I got the same problem, and I tried all possible > space groups for P222, but with other screw axis I can not even solve > the structure. > > A strange thing in the structure are the large solvent channels with a > lot of electron density positive peaks!? I usually did not see too > many peaks in the solvent channel like this. This peaks are the only > reason for these high R's in refinement that I can find. But, why are > there too many peaks in the solvent channel??? > > I put a .pdf file (ccp4bb_maps.pdf) with some more information and map > figures in this > link: https://dl.dropbox.com/u/16221126/ccp4bb_maps.pdf > > > Do someone have an explanation or solution for this? > > > > Cheers, > > Andrey > -- Edwin Pozharski, PhD, Assistant Professor University of Maryland, Baltimore ---------------------------------------------- When the Way is forgotten duty and justice appear; Then knowledge and wisdom are born along with hypocrisy. When harmonious relationships dissolve then respect and devotion arise; When a nation falls to chaos then loyalty and patriotism are born. ------------------------------ / Lao Tse /
