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The ability to both understand and generate accessible low-energy conformers is indispensable for small molecule drug discovery. There is however a gap between what is in principle known about conformation preferences and to what extend this knowledge is applied in day-to-day decision making in medicinal chemistry. We have addressed this gap with an expert-derived collection of patterns and rules that we make easily accessible with a new and interactive graphical software tool called TorsionAnalyzer.

torsion pattern analysis application example practical use case file browser

TorsionAnalyzer is based on an expert-derived collection of SMARTS patterns and rules (assigned peaks and tolerances). Rules result from statistical analysis of histograms derived from small molecule X-ray data extracted from the CSD. Rotatable bonds of molecules loaded into the TorsionAnalyzer are color-coded on the fly by means of a traffic light highlighting regular, borderline and unusual torsion angles. This allows the user to see at a glance if one or more torsion angles are out of the ordinary.

Confect is a new module in the TorsionAnalyzer that operates on the same database of preferred small molecules torsion angles and generates high-quality conformation ensembles. The TorsionAnalyzer interactive GUI allows you access the new function through a new menu entry. Please find a full description of the Confect method in a recent publication[3]. If you are interested in a separate command-line version of Confect, please contact us.

TorsionAnalyzer facilitates:

  • visual small molecule conformational analysis
  • interactive generation of high-quality conformation ensembles
  • expert modification of the torsion library
  • automatic generation and analysis of torsion distributions
  • direct access to histograms from CSD* and PDB
take a look at the TorsionAnalyzer tutorial movie

We recommend you to read the original publication[1] and try out TorsionAnalyzer for yourself.

Currently the free download is available only for academic users and contains limited CSD data*. Licensees of the CSD may download the full torsion data here. Any other interested users, please contact us. Also note that with the download you accept our terms and conditions**.

download TorsionAnalyzer
* Important notice:
TorsionAnalyzer may be used free of charge for academic research or evaluation purposes.
The TorsionAnalyzer version available for download does not contain the CSD histogram profiles. Their inclusion requires a license for the CSD available from the CCDC.
** Terms and conditions:
TorsionAnalyzer is a prototype developed by our academic partner at the Center for Bioinformatics (ZBH) of the University of Hamburg. No support is granted any warranty or liability is hereby expressly excluded. You use TorsionAnalyzer at your own risk!
Any publication in reference to TorsionAnalyzer must cite the original publication[1].
Please provide us your feedback. Also, if you are interested in a longer-term use or running TorsionAnalyzer on other operating systems, please let us know.
[1]Schärfer, C.; Schulz-Gasch, T.; Ehrlich, H.C.; Guba, W.; Rarey, M.; Stahl, M.
Torsion Angle Preferences in Drug-like Chemical Space: A Comprehensive Guide.
J. Med. Chem., 2013, 56 (5), pp 2016-2028
[2]Schulz-Gasch, T.; Schärfer, C.; Guba, W.; Rarey, M.
TFD: Torsion Fingerprints As a New Measure To Compare Small Molecule Conformations.
J. Chem. Inf. Model., 2012, 52 (6), pp 1499-1512
[3]Schärfer, C.; Schulz-Gasch, T.; Hert, J.; Heinzerling, L.; Schulz, B.; Inhester, T.; Stahl, M.; Rarey, M.
CONFECT: Conformations from an Expert Collection of Torsion Patterns
Chem. Med. Chem., 2013