> There are things you can expect to learn from a > 2Å structure that you are unlikely to learn from a 5Å structure, even > if equal care has been given to both experiments, so it makes sense > for the title to give the potential reader an idea which of the two > cases is presented. But for this purpose it isn't going to matter > whether "2Å" is really 1.8Å or 2.2Å.
What should the title say when a crystal diffracts to, lets say, 3 A in one direction and 4-5 A in others? Alex Aleshin, Sanford-Burnham Medical Research Institute 10901 North Torrey Pines Road La Jolla, California 92037 On May 31, 2012, at 2:50 PM, Ethan Merritt wrote: > On Thursday, May 31, 2012 02:21:45 pm Dale Tronrud wrote: >> The resolution limit of the data set has been such an important >> indicator of the quality of the resulting model (rightly or wrongly) >> that it often is included in the title of the paper itself. Despite >> the fact that we now want to include more, weak, data than before >> we need to continue to have a quality indicator that readers can >> use to assess the models they are reading about. While cumbersome, >> one solution is to state what the resolution limit would have been >> had the old criteria been used, as was done in the paper you quote. >> This simply gives the reader a measure they can compare to their >> previous experiences. > > [\me dons flame suit] > > To the extent that reporting the resolution is simply a stand-in > for reporting the quality of the model, we would do better to cut > to the chase. For instance, if you map the Molprobity green/yellow/red > model quality scoring onto good/mediocre/poor then you can title > your paper > > Crystal Structure of Fabulous Protein Foo at Mediocre Quality > > [\me removes flame suit from back, and tongue from cheek] > > > More seriously, I don't think it's entirely true that the resolution > is reported as an indicator of quality in the sense that the model > is well-refined. There are things you can expect to learn from a > 2Å structure that you are unlikely to learn from a 5Å structure, even > if equal care has been given to both experiments, so it makes sense > for the title to give the potential reader an idea which of the two > cases is presented. But for this purpose it isn't going to matter > whether "2Å" is really 1.8Å or 2.2Å. > >> Now would be a good time to break with tradition and institute >> a new measure of quality of diffraction data sets. I believe several >> have been proposed over the years, but have simply not caught on. >> SFCHECK produces an "optical resolution". Could this be used in >> the title of papers? I don't believe it is sensitive to the cutoff >> resolution and it produces values that are consistent with what the >> readers are used to. With this solution people could include whatever >> noisy data they want and not be guilty of overstating the quality of >> their model. > > We should also encourage people not to confuse the quality of > the data with the quality of the model. > > Ethan > > -- > Ethan A Merritt > Biomolecular Structure Center, K-428 Health Sciences Bldg > University of Washington, Seattle 98195-7742
