Are your 3 crystals isomorphous, and do they all refine well? I guess you struck lucky with DS3 - as suggested it could be a different soaking, different crystal size, etc, etc..
If isomorphous I would compare all 3 structures in COOT and look for subtle differences.. Your C222 and C2221 cells are obviously related but have slightly different cell volumes so cannot be exactly the same. Do you have any non-crystallographic translation - that can confuse the assignment of 2_1 axes. Eleanor On 26 October 2016 at 15:47, Tristan Croll <ti...@cam.ac.uk> wrote: > Are these three crystals in order of harvesting (with different soaking > times)? How big is your ligand. How accessible is the binding pocket (and > is there a clear difference in accessibility between chains)? > > T > > > > Tristan Croll > Research Fellow > Cambridge Institute for Medical Research > University of Cambridge CB2 0XY > > > > > > On 26 Oct 2016, at 13:32, Veronica Fiorentino < > veronicapfiorent...@gmail.com> wrote: > > > > Hello all, > > I just solved a NCS-tetrameric (biological assembly is just a dimer) > crystal structures with ligand soak (same plate - same conditions). No > density for ligand is observed in the first map. In the 2nd, I have 1 > ligand bound. In the 3rd, I have 2 ligands bound. Is there any reason for > this 'random' behaviour? > > > > In addition, I observed just one crystal out of 20 gave a different unit > cell. Pointless confirms to me > > "Best Solution: space group C 2 2 2". REFMAC refinement shows R/Rfree > ~ 20/25 % > > Cell from mtz : 216.5 345.8 145.2 90.0 90.0 90.0 > > Space group from mtz: number - 21; name - C 2 2 2 > > > > All other datasets have: > > Cell from mtz : 147.0 354.3 217.4 90.0 90.0 90.0 > > Space group from mtz: number - 20; name - C 2 2 21 > > > > I tried re-processing/refining the C2221 dataset in C222 but R/Rfree > stays ~45%. Can I also consider the C2221 dataset as a 'different crystal > form'? > > > > Am I safe? > > > > Thank you all, > > Veronica >
