Ramaswamy Nilakantan

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We develop an extension of conventional distance geometry techniques that treats two or more molecules as a single "ensemble". This extension can be used to find a common pharmacophore, i.e., the spatial arrangement of essential groups, from a small set of biologically active molecules. The approach can generate, in one step, coordinates for the set of(More)
We present a method for the rapid quantitative shape match between two molecules or a molecule and a template, using atom triplets as descriptors. This technique can be used either as a rapid screen preceding the computationally expensive shape-based docking method developed by Kuntz and co-workers or as a stand-alone method to rank compounds in a large(More)
We present some new ideas for characterizing and comparing large chemical databases. The comparison of the contents of large databases is not trivial since it implies pairwise comparison of hundreds of thousands of compounds. We have developed methods for categorizing compounds into groups or series based on their ring-system content, using precalculated(More)
Several efficient correspondence graph-based algorithms for determining the maximum common substructure (MCS) of a pair of molecules have been published in the literature. The extension of the problem to three or more molecules is however nontrivial; heuristics used to increase the efficiency in the two-molecule case are either inapplicable to the(More)
A novel method for generation of chemical structures of potential pharmaceutical interest is presented. Structures are generated by random combination of known fragments and selected by statistical topological techniques. The power of the method lies in the great profusion of candidates generated together with the extremely high selectivity imposed by the(More)
A novel algorithm for the connecting of fragment molecules is presented and validated for a number of test systems. Within the CONFIRM (Connecting Fragments Found in Receptor Molecules) approach a pre-prepared library of bridges is searched to extract those which match a search criterion derived from known experimental or computational binding information(More)
Calicheamicin gamma 1I is a recently discovered diyne-ene-containing antitumor antibiotic that cleaves DNA in a double-stranded fashion, a rarity among drugs, at specific sequences. It is proposed that the cutting specificity is due to a combination of the complementarity of the diyne-ene portion of the aglycone with DNA secondary structures and(More)