Hi, Dear CCP4 group, I recently collect one dataset and indexed as P4 space group. When I try to do MR with a tetramer as input, I found the solution file suggested P41.
SOLU SET RFZ=5.2 TFZ=10.3 PAK=0 LLG=239 LLG=366 TFZ==20.9 SOLU SPAC P 41 SOLU 6DIM ENSE ensemble1 EULER 50.265 0.217 219.800 FRAC 0.50029 0.49916 -0.00408 BFAC -0.04000 SOLU ENSE ensemble1 VRMS 0.639 SOLU SET RFZ=5.2 TFZ=10.0 PAK=0 LLG=239 TFZ==11.2 LLG=365 SOLU SPAC P 41 SOLU 6DIM ENSE ensemble1 EULER 128.607 179.813 38.677 FRAC 0.49991 0.49905 -0.00208 BFAC -0.06264 SOLU ENSE ensemble1 VRMS 0.642 However when I did refinement in phenix, I have some trouble getting the R/Rfree down. It complains about some twinning or maybe higher symmetry like P422. When I apply twin law, h,-k,-l, I'm able to refine to 0.34/0.37 but still, hard to continue the refinement. The strategy I used for refinement is xyz coordinates, real-space, individual B-factors, occupancies, with NCS restraints and twin law. So I tried to rescaled into P41212 space group, and run MR again, with two chains as an input and found one solution SOLU SET RFZ=4.5 TFZ=9.5 PAK=0 LLG=115 TFZ==10.0 LLG=118 TFZ==10.4 SOLU SPAC P 41 21 2 SOLU 6DIM ENSE ET EULER 234.6 0.7 305.0 FRAC 1.00 0.49 -0.17 BFAC -0.14 Ensemble ET RMS variance(s): 0.96 However, when i tried to refine, the Rfree is high as 0.51 at the first round. Does this mean this is not the right solution or maybe some problems with the space group?Any suggestions for next step? Thanks very much.
