Torsion Library

Crystal structure databases offer ample opportunities to derive small molecule conformation preferences. We developed a comprehensive and expandable expert system that enables users to quickly assess the occurrence likelihood of a given molecular conformation.[1] It relies on a hierarchical system of torsion patterns covering a large part of drug-like chemical space.[2] Each torsion pattern has associated frequency histograms generated from data stored in the Cambridge Structural Database (CSD) and the Protein Data Bank (PDB). From the histograms, we derived traffic-light rules for frequently observed, rare, and highly unlikely torsion angle ranges. Users can find details on the library and its usage in the corresponding publications.

The full histograms derived from CSD data could not be published for the 2013[2] and 2016[3] Torsion Library due to legal restrictions. However, with the 2022 version of the Torsion Library, which includes CSD as well as PDB histograms, the complete torsion pattern library, including preferred angles and derived tolerances, is available as Supporting Information of the corresponding publication.[4] We also intend to provide further updates on the library and derived data here.

• Version 3.0 [Torsion Library 2022] https://pubs.acs.org/doi/suppl/10.1021/acs.jcim.2c00043/suppl_file/ci2c00043_si_002.zip
• Version 2.0 [Torsion Library 2016] https://www.zbh.uni-hamburg.de/forschung/amd/datasets/torsion-library/tor-lib-2016.zip
• Version 1.0 [Torsion Library 2013] https://www.zbh.uni-hamburg.de/forschung/amd/datasets/torsion-library/tor-lib-2013.zip

[1] Ehrlich, H. C.; Rarey, M. Systematic Benchmark of Substructure Search in Molecular Graphs - From Ullmann to VF2. J Cheminform 2012, 4 (1), 13. DOI: https://doi.org/10.1186/1758-2946-4-13
[2] Schärfer, C.; Schulz-Gasch, T.; Ehrlich, H. C.; Guba, W.; Rarey, M.; Stahl, M. Torsion Angle Preferences in Druglike Chemical Space: A Comprehensive Guide. J Med Chem 2013, 56 (5), 2016-2028. DOI: https://doi.org/10.1021/jm3016816
[3] Guba, W.; Meyder, A.; Rarey, M.; Hert, J. Torsion Library Reloaded: A New Version of Expert-Derived SMARTS Rules for Assessing Conformations of Small Molecules. J Chem Inf Model 2016, 56 (1), 1-5. DOI: https://doi.org/10.1021/acs.jcim.5b00522
[4] Penner, P.; Guba, W.; Schmidt, R.; Meyder, A.; Stahl, M.; Rarey, M. The Torsion Library: Semiautomated Improvement of Torsion Rules with SMARTScompare. J Chem Inf Model 2022, 62 (7), 1644-1653. DOI: https://doi.org/10.1021/acs.jcim.2c00043