Hi Bernhard, I just calculated k_sol and B_sol for all PDB entries that - have reflection data available, - I could re-compute the R-factor within 5%, and - R-work<30% using a simple cctbx script. Here is what I get:
Distribution of k_sol: 0.000 - 0.060 : 27 0.060 - 0.120 : 12 0.120 - 0.180 : 51 0.180 - 0.240 : 182 0.240 - 0.300 : 1770 0.300 - 0.360 : 13819 0.360 - 0.420 : 19731 0.420 - 0.480 : 3039 0.480 - 0.540 : 471 0.540 - 0.600 : 256 Distribution of B_sol: 0.000 - 31.300 : 4349 31.300 - 62.600 : 29425 62.600 - 93.900 : 4578 93.900 - 125.200 : 597 125.200 - 156.500 : 225 156.500 - 187.800 : 84 187.800 - 219.100 : 37 219.100 - 250.400 : 23 250.400 - 281.700 : 10 281.700 - 313.000 : 30 It seems like the result of similar exercise done by Fokine and Urzhumtsev (Acta Cryst. (2002). D58, 1387-1392) still holds (see figure 3 on page 1390 there). Pavel On Mon, Jan 30, 2012 at 11:10 AM, Bernhard Rupp (Hofkristallrat a.D.) < hofkristall...@gmail.com> wrote: > Dear All, > > when I plot bulk solvent B and K extracted from EDS, an improbable and > bimodal distribution appears. > In the B_sol vs k_sol PDF a sharp line of values with B-sol of 70 appears > (B-axis left to right, 0-200). > > http://www.ruppweb.org/images/b_sol_contour.jpg > http://www.ruppweb.org/images/b_sol_surface.jpg > > According to a quick peak at EDS instructions, > it uses the REFMAC flat bulk solvent model throughout for bulk solvent > correction. > > The main peak in fact has the expected distribution, but it seems that the > sharp peak at B_sol=70 > represents some cut-off that in a certain set of calculations was used. > > For data mining it would be useful to know where/when these cutoffs were > used. > > Best regards, BR > ----------------------------------------------------------------- > Bernhard Rupp > http://www.ruppweb.org/ > ----------------------------------------------------------------- >