System and method for confirmationally-flexible molecular identification

Abstract

A reference storage process populates a data structure so that the data structure contains all of the molecular structures and/or rigid substructures in the database classified according to attributes of tuples. In a preferred embodiment, the tuples are derived from sites (e.g. atomic sites) of the molecular structures and the attributes can be derived from geometric (and other) information related to the tuples. The attributes are used to define indices in the data structure that are associated with invariant vector information (e.g. information about rotatable bond(s) in skewed local coordinate frames created from tuples). These representations are invariant with respect to the rotation and translation of molecular structures and/or the rotation of substructures about attached rotatable bond(s). Accordingly, the invariant vector information is classified in the data structure with the respective tuple attributes in locations determined by the index derived from the respective tuple. A matching process creates one or more tuples, skewed local reference frames, and indices (called test frame tuple indices) for the structure (substructures) of a test molecule using the same technique that was used to populate the data structure. The test frame tuple index accesses the invariant vector information and tallies the frequency of matching in order to determine the identity of molecules/substructures in the database that are structurally similar to the test molecule. This identification can be achieved even in the presence of conformationally flexible molecules in the database.