Dear Michael, as said in this thread, careful re-integration (or other programs) might give you better data. If using XDS, you could try RELRAD=7 (or even 10 if the background is very low; the default is 5) in INTEGRATE (this as yet undocumented option is in the latest XDS and determines the radius of the background area relative to that of the peak; BEAM_DIVERGENCE/BEAM_DIVERGENCE_E.S.D.) Of course, all other optimiatzion options should be tried..
On the other hand (and again as others already said), some of the stats look strange - the CC1/2 of 53% asks for extending the resolution, whereas the low <I/sigma> of 0.1 says it won't help much. You can evaluate radiation damage with the R_d plot from XDSSTAT. This is most easily produced and interpreted in XDSGUI - if the red fit line intersects the green level then this means that after this many frames, radiation damage starts dominating all other sources of error. Most importantly - which problem do you really need to solve? 3.5A structures are not unheard of, and can be published and deposited. Another 0.1A higher resolution may not help much. Is there a problem in refinement or map interpretation? What is current Rwork/Rfree overall and in the highest shell? best, Kay On Thu, 18 May 2017 11:47:30 +0000, Michael Jarva <m.ja...@latrobe.edu.au> wrote: >Dear all, > >I have a dataset that have two very interesting properties: a) It's in I432, >and b) has a whooping 75% solvent content. >You might think that the solvent content obviously is a big red flag, and so >did I, but I have phased this successfully with just one monomer, and the >packing result does makes a lot of sense. The resulting maps contain no extra >umodelled blobs, and trying to phase it with an additional molecules does not >give a good solution. > >The problem I have is that the diffraction intensity/Rmerge plummets/explodes >around the 3.5� mark (I assume because of the high solvent content) to such an >extent that even though I have little radiation damage, 100% completeness in >high resolution shells, and very high redundancy, any attempt to merge the >dataset at a higher resolution has so far given no improvement to the maps. > >I'm hoping that there might be a few tricks out there I can apply to the spot >finding/integration/scaling steps have it merge in a even slightly higher >resolution than I currently have been able to do. >Although I have a feeling that the only thing I can do is to grow another, >much bigger, crystal� > >many thanks for any feedback >/michael > >See below for sample outputs from aimless: > > Overall InnerShell OuterShell >Low resolution limit 43.50 43.50 3.32 >High resolution limit 3.10 8.78 3.10 > >Rmerge (within I+/I-) 0.079 0.010 21.891 >Rmerge (all I+ and I-) 0.081 0.011 22.502 >Rmeas (within I+/I-) 0.084 0.011 23.102 >Rmeas (all I+ & I-) 0.084 0.011 23.169 >Rpim (within I+/I-) 0.027 0.004 7.335 >Rpim (all I+ & I-) 0.020 0.003 5.450 >Rmerge in top intensity bin 0.010 - - >Total number of observations 34917 1495 6448 >Total number unique 2057 112 362 >Mean((I)/sd(I)) 18.3 130.9 0.1 >Mn(I) half-set correlation CC(1/2) 1.000 1.000 0.533 >Completeness 99.9 97.4 100.0 >Multiplicity 17.0 13.3 17.8 > > Overall InnerShell OuterShell >Low resolution limit 43.50 43.50 3.84 >High resolution limit 3.50 8.58 3.50 > >Rmerge (within I+/I-) 0.052 0.011 2.422 >Rmerge (all I+ and I-) 0.056 0.012 2.659 >Rmeas (within I+/I-) 0.055 0.011 2.553 >Rmeas (all I+ & I-) 0.058 0.013 2.738 >Rpim (within I+/I-) 0.017 0.004 0.804 >Rpim (all I+ & I-) 0.014 0.003 0.644 >Rmerge in top intensity bin 0.010 - - >Total number of observations 24596 1690 6071 >Total number unique 1462 120 343 >Mean((I)/sd(I)) 25.8 132.0 1.0 >Mn(I) half-set correlation CC(1/2) 1.000 1.000 0.771 >Completeness 99.8 97.6 100.0 >Multiplicity 16.8 14.1 17.7 > >
