Computer implemented method for aligning flexible molecules by performing ensemble alignment in the internal coordinate space followed by rigid body alignment in cartesian space
A method is disclosed that overcomes the problem in the prior art of requiring the use of a template or base molecule in order to compare the three dimensional configurations of molecules. The disclosed method teaches that the requirement for a template can be eliminated by handling the components of configuration—conformation versus rotation and translation in three-dimensional space—separately. The internal coordinate (torsional) space is explored first using a multi-objective genetic algorithm to minimize strain while maximizing steric and pharmacophoric concordance. Optimal overlays in Cartesian space are then obtained by applying a 3D hypermolecule construction method that makes use of linear assignment to identify optimal feature correspondences between ligands.
1 . A computer-implemented method for aligning flexible molecules in three dimensions comprising the following steps:
a) selecting a conformer of each molecule in a data set such that the selected conformers are concordant in the respective internal coordinate spaces; and
b) aligning in Cartesian space based upon shared molecular spatial characteristics of selected conformers.
2 . The method of claim 1 in which the selection in step a is performed by a genetic algorithm that utilizes variable indexing.
3 . A method of claim 1 in which the aligned molecules are used to create a pharmacophoric search query.
4 . A method of claim 2 in which the aligned molecules are used to create a pharmacophoric search query.