Hi, Micheal: Thank you for your comments. I am getting to know where is the problem. Sorry that I did not give the information of my datasets in details.
Here are the answears of the some of the concerns: > 1) putative space group? P2 or P21. > 2) observed resolution 50 - 1.5 A > 3) how big was the crystal and what was its shape? Was the crystal split? Crystals is abot 100 um x 20 um x 20 um. Thesy are thin rods. The crystal is not split. > 4) were the data sets taken at different points on the crystal? Is radiation damage a factor? The data sets were taken at different points on the crystal. Radiation damage is not a facotr. > 5) did you just rotate around phi (or omega) to collect the different data sets or did you change the other angular settings? Collections were taken at one direction along the long side of the crystal, at diffrent spots. > 6) are all your data sets indexed in exactly the same way Yes, each can be index and intergrate individually without any probelm using HKL. But I can not combine them togehter using just one standard. I notice that the cell deminsions are diffrent from these sets. As you and other suggested, non-uniformity in a large crystal may be the cause. I will try to use other program as suggested by many of you. Thank you very much for all your inputs Uma On Thu, Aug 2, 2012 at 9:04 AM, R. M. Garavito <[email protected]> wrote: > Uma, > > Before this discussion goes much further, you need to provide more details: > > 1) putative space group? > > 2) observed resolution and diffraction anisotropy? > > 3) how big was the crystal and what was its shape? Was the crystal split? > > 4) were the data sets taken at different points on the crystal? Is > radiation damage a factor? > > 5) did you just rotate around phi (or omega) to collect the different data > sets or did you change the other angular settings? > > 6) are all your data sets indexed in exactly the same way (a tricky and > non-obvious factor for a novice to appreciate). Using pointless on > unmerged data sets helps with this. > > You have a number of unknowns here, and your problem in merging the data > sets may be due to radiation damage, non-uniformity in a large crystal, > index refinement problems due to diffraction anisotropy, etc. We routinely > merge different data sets from a single crystal, which has been translated > and rotated about one axis only. We try to index and process the data sets > using a common setting matrix (which is easy with XDS). However, sometimes > it just does work, but merging pairs of data sets often allowed us to > discard the worst offender(s). > > Good luck, > > Michael > > ****************************************************************** > *R. Michael Garavito, Ph.D.* > *Professor of Biochemistry & Molecular Biology* > *603 Wilson Rd., Rm. 513** * > *Michigan State University * > *East Lansing, MI 48824-1319* > *Office:** **(517) 355-9724 Lab: (517) 353-9125*** > *FAX: (517) 353-9334 Email: [email protected]* > ****************************************************************** > > > > > On Aug 1, 2012, at 4:37 PM, Uma Ratu wrote: > > I notice one thing with my data sets. > > The unit cells is slightly different from each other. For example, one has > a/b/c @ 79/126/83. The other has a/b/c @ 84/127/90. Although they are > collected from the same crystal. > > Is this the reason that I can't index both with same parameter in HKL? And > subsequently, can't integrate and scala together. If so, is there a way > that I can fix it? > > Thank you for your advice > > Uma > On Wed, Aug 1, 2012 at 8:50 AM, Uma Ratu <[email protected]> wrote: > >> Dear All: >> >> I collected 5 data sets from one crystal and would like to process them >> together. >> >> Here is how I did: >> >> In HKL2000, load the all data sets. "Index" each set. When I try >> "Intergrate", the program automatically go through the whole data sets >> there, and do not go through. >> >> I then process data sets by loading one at each time. Index, intergrate >> and scale all go through very smoothly. But when I put them together, the >> program just goes crazy. >> >> Thank you for advice >> >> Uma >> > > >
