>>It would seem to me that an important issue is also: do get all information >>out of our diffraction data? By integrating the Bragg peaks we usually >>neglect the diffuse scattering that could potentially contain additional >>(dynamic) structural information. This can be cloudy diffuse scattering >>hidden in the background but also diffuse streaks that contain information on >>packing disorder and reveals intrinsic interactions in the crystal.
Along these lines, and taking a page from you also, how about "crystallographic model refinement as image-faking?" Metrics of the goodness of a particular refinement could simply be some measure of the correlation between predicted vs. measured images. I have seen some of this done with diffuse scattering, but why not with the whole thing, including intensity and shape of Bragg peaks, solvent rings, etc? Maybe instead of doing the multiple steps of (indexing, integration, scaling, solving...) all of this could be refined as one? Processing parameters like moscaicity [sic] etc would now be part of the final model...? JPK Loes Kroon-Batenburg On 07/15/19 21:44, Holton, James M wrote: Hello folks, I have the distinct honor of chairing the next Gordon Research Conference on Diffraction Methods in Structural Biology (July 26-31 2020). This meeting will focus on the biggest challenges currently faced by structural biologists, and I mean actual real-world challenges. As much as possible, these challenges will take the form of friendly competitions with defined parameters, data, a scoring system, and "winners", to be established along with other unpublished results only at the meeting, as is tradition at GRCs. But what are the principle challenges in biological structure determination today? I of course have my own ideas, but I feel like I'm forgetting something. Obvious choices are: 1) getting crystals to diffract better 2) building models into low-resolution maps (after failing at #1) 3) telling if a ligand is really there or not 4) the phase problem (dealing with weak signal, twinning and pseudotranslation) 5) what does "resolution" really mean? 6) why are macromolecular R factors so much higher than small-molecule ones? 7) what is the best way to process serial crystallography data? 8) how should one deal with non-isomorphism in multi-crystal methods? 9) what is the "structure" of something that won't sit still? What am I missing? Is industry facing different problems than academics? Are there specific challenges facing electron-based techniques? If so, could the combined strength of all the world's methods developers solve them? I'm interested in hearing the voice of this community. On or off-list is fine. -James Holton MAD Scientist ######################################################################## To unsubscribe from the CCP4BB list, click the following link: https://www.jiscmail.ac.uk/cgi-bin/webadmin?SUBED1=CCP4BB&A=1<https://urldefense.proofpoint.com/v2/url?u=https-3A__www.jiscmail.ac.uk_cgi-2Dbin_webadmin-3FSUBED1-3DCCP4BB-26A-3D1&d=DwMFAw&c=LU6cRtx0xgB8s29tIz9Olw&r=eLCg9eJ4Rs_LnxfUWsp7FSxhIEcZYmTSU4Uyq1bRYPI&m=j60Req0Ctc22ORJ8Tr5oxj6jiKrZs6a6a3qScsFKgfg&s=nvFe-NBmWDef18CvLm-0QKC6gd9nDyAZxKO5eEZ7t1I&e=> -- __________________________________________ Dr. Loes Kroon-Batenburg Dept. of Crystal and Structural Chemistry Bijvoet Center for Biomolecular Research Utrecht University Padualaan 8, 3584 CH Utrecht The Netherlands E-mail : l.m.j.kroon-batenb...@uu.nl<mailto:l.m.j.kroon-batenb...@uu.nl> phone : +31-30-2532865 fax : +31-30-2533940 __________________________________________ ________________________________ To unsubscribe from the CCP4BB list, click the following link: https://www.jiscmail.ac.uk/cgi-bin/webadmin?SUBED1=CCP4BB&A=1<https://urldefense.proofpoint.com/v2/url?u=https-3A__www.jiscmail.ac.uk_cgi-2Dbin_webadmin-3FSUBED1-3DCCP4BB-26A-3D1&d=DwMFAw&c=LU6cRtx0xgB8s29tIz9Olw&r=eLCg9eJ4Rs_LnxfUWsp7FSxhIEcZYmTSU4Uyq1bRYPI&m=j60Req0Ctc22ORJ8Tr5oxj6jiKrZs6a6a3qScsFKgfg&s=nvFe-NBmWDef18CvLm-0QKC6gd9nDyAZxKO5eEZ7t1I&e=> ######################################################################## To unsubscribe from the CCP4BB list, click the following link: https://www.jiscmail.ac.uk/cgi-bin/webadmin?SUBED1=CCP4BB&A=1
