Have a look at local distance difference test.https://swissmodel.expasy.org/lddt/ It's superposition-free and compares local atomic environment only. You will be able to see unusually different regions from the output.
I am not aware of a similar structure comparison method that would also take into account the underlying data, you'll probably need to come up with something here. E.g. place one structure instead of another in its crystal and evaluate local electron density correlations along the sequence (sfcheck can do that I think) at different resolution levels. Then compare changes in local correlation (replaced-original) vs. lddt plot. If both plots go down in the same region, then it warrants a closer look. Kind regards, Dmytro. On 10/04/17 01:37, Reza Khayat wrote:
Hi, My initial e-mail may have been a bit vague so I'll try to be more specific. Superposing the structures and comparing them against one another, while appropriate, is a subjective way to do the analysis as I would have to subjectively define a threshold that would indicate a difference between the structures. My threshold may be grossly different than someone else's threshold. I am interested in an objective criterion. One where strong emphasis has been put on error analysis and error modeling in terms of both the refined structure and the underlying data. I realize that defining such criterion is by no means trivial. Thanks again for the help. Best wishes, Reza Reza Khayat, PhD Assistant Professor City College of New York Department of Chemistry New York, NY 10031 ________________________________________ From: Reza Khayat Sent: Sunday, April 9, 2017 6:07 PM To: CCP4 bulletin board Subject: Structure comparison Hi, I have refined several structures of a protein from different space groups and would like to compare them to one another. Is there a program/software suite that would provide an objective comparison of the structures and identify regions where the structures are sufficiently different from one another to warrant a closer look? I think the most important aspect of the analysis would be defining a threshold (possibly based on resolution and structure statistics) that would identify sufficient difference between structures. Thanks. Best wishes, Reza Reza Khayat, PhD Assistant Professor City College of New York Department of Chemistry New York, NY 10031
