Computer programs CONCORD

Computation time. CONCORD required extremely short computation times (0.14 sec/molecule), whereas MOLGEO, CONVERTER, and COBRA needed substantially larger times (3.49-8.98 sec/molecule). All other programs needed times of less than 1 sec/molecule. The computation times refer to the number of structures converted by the different programs. 

The last few years have seen substantial interest in the development of database-searching systems for files of 3D structures. The atom coordinate information in such databases is obtained either experimentally, usually from the Cambridge Structural Database, which contains X-ray structures that have been reported in the published literature,or by the use of a struaure-builder, which is a computer program that calculates an approximate 3D structure from a 2D connection table. - The best known of such programs is CONCORD, which uses a knowledge base of rules that describe preferred molecular conformational patterns and a simplified force-field. CONCORD has been widely used for the conversion of both in-house and public databases of 2D structures to 3D form. 

Another related computational approach to ligand discovery is the method of database mining. Here, the HTS approach is essentially carried out in-silico. Libraries of small molecules are converted to three-dimensional structures using molecular mechanics methods incorporated into programs such as CONCORD and GORINA.These three-dimensional libraries of small molecules can. in theory, contain almost infinite numbers of potential ligands. In practice, it is convenient to consider compounds that are already (commercially) available. The Available Chemicals Database (ACD), - for example, contains some 260,000 compounds and is frequently used as the basis for database mining trials. 

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