Re: [ccp4bb] anisotropic diffraction in refinement
There is a ellipsoidal truncation and scaling server you might want to try. http://www.doe-mbi.ucla.edu/~sawaya/anisoscale/ ~L~ __ Lari Lehtiö Pharmacy, Department of Biochemistry and Pharmacy Åbo Akademi University, BioCity, FIN-20520 Turku Finland +358 2 215 4270 __ Quoting Justin Hall : Dear All; I am working with a data set which is anisotropic. The resolution limits are ~ 2.75 by 3.45 A. The I have integrated (using Mosflm) the data out to 2.75 A, the data therefore includes a mix of real (I/sig 1) and imaginary (I/sig ~1) data past the 3.45 A resolution bin. I am concerned that the presence of the poor quality data in the outer shells will cause my good data to 2.75 A resolution to be down weighted in refinement. Since anisotropic resolution limits do not seem to be an option, are there other tools that would allow proper weighting for this situation? Cheers~ ~Justin Hall Oregon State University
Re: [ccp4bb] anisotropic diffraction in refinement
Hi Justin, may be I mis-understood your question, but can't anisotropic scale factor that is the part of the total structure factor (as defined in phenix.refine for example and most likely in the other programs): Fmodel = scale_overall * exp(-h*U_overall*ht) * (Fcalc_atoms + k_sol * exp(-B_sol*s^2) * Fmask) take care of this (S. Sheriff & W.A. Hendrickson. Acta Cryst. (1987). A43, 118-121. "Description of overall anisotropy in diffraction from macromolecular crystals")? For an example of how important to use anisotropic scale for anisotropy correction, see slide #20 here: http://phenix-online.org/presentations/neutron_japan_2009/phenix_japan_part1.pdf Pavel. On 9/1/09 7:35 AM, Justin Hall wrote: Dear All; I am working with a data set which is anisotropic. The resolution limits are ~ 2.75 by 3.45 A. The I have integrated (using Mosflm) the data out to 2.75 A, the data therefore includes a mix of real (I/sig >>1) and imaginary (I/sig ~1) data past the 3.45 A resolution bin. I am concerned that the presence of the poor quality data in the outer shells will cause my good data to 2.75 A resolution to be down weighted in refinement. Since anisotropic resolution limits do not seem to be an option, are there other tools that would allow proper weighting for this situation? Cheers~ ~Justin Hall Oregon State University
[ccp4bb] anisotropic diffraction in refinement
Dear All; I am working with a data set which is anisotropic. The resolution limits are ~ 2.75 by 3.45 A. The I have integrated (using Mosflm) the data out to 2.75 A, the data therefore includes a mix of real (I/sig >>1) and imaginary (I/sig ~1) data past the 3.45 A resolution bin. I am concerned that the presence of the poor quality data in the outer shells will cause my good data to 2.75 A resolution to be down weighted in refinement. Since anisotropic resolution limits do not seem to be an option, are there other tools that would allow proper weighting for this situation? Cheers~ ~Justin Hall Oregon State University
