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Volume 2, Number 4, 1999: Contents

Fluorescence Polarization: An Analytical Tool for Immunoassay and Drug Discovery. Pp. 177-190.
Mohammad Sarwar Nasir and Michael E. Jolley
[Abstract]

Recent Advances in the Solid Phase Synthesis of Drug-Like Heterocyclic Small Molecules. Pp. 191-210.
C. J. Andres, Derek J. Denhart, Milind S. Deshpande and Kevin W. Gillman
[Abstract]

Structure-Based Drug Design: Combinatorial Chemistry and Molecular Modeling. Pp. 211-221.
D. Lynn Kirkpatrick, Shawndra Watson and Saraj Ulhaq
[Abstract]

Small Molecule Recognition: Solid Angles Surface Representation and Molecular Shape Complementarity. Pp. 223-237.
R. Norel, H. J. Wolfson and R. Nussinov
[Abstract]

Inventory Management and Reagent Supply for Automated Chemistry. Pp. 239-247.
Ed Kuzniar
[Abstract]


Abstracts

[Back to top] Fluorescence Polarization: An Analytical Tool for Immunoassay and Drug Discovery. Mohammad Sarwar Nasir and Michael E. Jolley.
Fluorescence polarization (FP) is an intrinsically powerful technique for the rapid and homogeneous analysis of molecular interactions in biological/chemical systems. The technique has been successfully used to diagnose various viral and infectious diseases in humans and animals, to monitor therapeutic drug levels and substances of abuse in body fluids and to determine food born pathogens, grain mycotoxins and pesticides. It has also been used in monitoring enzyme catalyzed hydrolysis, protein-protein interactions, DNA diagnostics and high throughput screening during the course of drug discovery. Work by various groups, including our own, have demonstrated that the technique can replace a substantial number of solid phase assays. FP, defined by the equation P = [IV - IH] / [IV + IH] (where V and H are the vertical and horizontal components of the intensity I of emitted light respectively when exited by vertically plane polarized light), is independent of the intensity of the light and the concentration of the fluorophore. Hence it is functional in colored and cloudy solutions. The FP of a fluorophore is proportional to its rotational relaxation time, which in turn depends upon its molecular volume (or molecular weight) at constant temperature and solution viscosity. When a fluorophore-labeled ligand binds to a larger molecule, equilibrium is established rapidly and the FP increases. This property has been successfully exploited in many fields as described in this review.

[Back to top] Recent Advances in the Solid Phase Synthesis of Drug-Like Heterocyclic Small Molecules. C. J. Andres, Derek J. Denhart, Milind S. Deshpande and Kevin W. Gillman.
Because of their synthetic challenge, broad range of physical / chemical properties, and diverse biological activities, heterocycles continue to be of interest to both the academic and industrial chemist. This review covers recent advances in the solid phase synthesis of drug-like heterocyclic small molecules. Syntheses which form the heterocycle on the solid phase are emphasized; syntheses in which a preformed heterocycle is functionalized on the solid support have been omitted. The majority of references are from publication year 1999. This review should be of interest to anyone involved in, or contemplating the solid phase synthesis of small molecule drug-like heterocycles, especially for combinatorial chemistry applications.

[Back to top] Structure-Based Drug Design: Combinatorial Chemistry and Molecular Modeling. D. Lynn Kirkpatrick, Shawndra Watson and Saraj Ulhaq.
Drug discovery efforts are shifting to include the rapid synthetic procedures of combinatorial chemistry and the elegance of rational library design. The wealth of computational methods which explore both the receptor structure and the ultimate pharmacophore complementarity, provide novel avenues for chemists to discover new lead compounds or design virtual libraries for screening prior to the synthetic stage. This mini-review provides an overview of a few current methodologies of library generation, highlighting docking procedures which have utility in both the discovery and optimization stages of drug development. Three specific examples of different approaches to the use of docking are provided. These describe the development of inhibitors to the human A3 adenosine receptor and HIV-1 protease, and the evaluation of the activity of novel inhibitors of the redox regulator protein, human thioredoxin.

[Back to top] Small Molecule Recognition: Solid Angles Surface Representation and Molecular Shape Complementarity. .
Here we examine the recognition of small molecules by their protein and DNA receptors. We focus on two questions: First, how well does the solid angle molecular surface representation perform in fitting together the surfaces of small ligands, such as drugs and cofactors to their corresponding receptors; And second, in particular, to what extent does the shape complementarity play a role in the matching (recognition) process of such small molecules. Both questions have been investigated in protein-protein binding: "Critical Points" based on solid angle calculations have been shown to perform well in the matching of large protein molecules. They are robust, may be few in numbers, and capture satisfactorily the molecular shape. Shape complementarity has been shown to be a critical factor in protein-protein recognition, but has not been examined in drug-receptor recognition. To probe these questions, here we dock 185 receptor-small ligand molecule pairs. We find that such a representation performs adequately for the smaller ligands too, and that shape complementarity is also observed. These issues are important, given the large databases of drugs that routinely have to be scanned to find candidate, lead compounds.

We have been able to carry out such large scale docking experiments owing to our efficient, computer-vision based docking algorithms. Its fast CPU matching times, on the order of minutes on a PC, allows such large scale docking experiments.

[Back to top] Inventory Management and Reagent Supply for Automated Chemistry. Ed Kuzniar.
Developments in automated chemistry have kept pace with developments in HTS such that hundreds of thousands of new compounds can be rapidly synthesized in the belief that the greater the number and diversity of compounds that can be screened, the more successful HTS will be. The increasing use of automation for Multiple Parallel Synthesis (MPS) and the move to automated combinatorial library production is placing an overwhelming burden on the management of reagents. Although automation has improved the efficiency of the processes involved in compound synthesis, the bottleneck has shifted to ordering, collating and preparing reagents for automated chemistry resulting in loss of time, materials and momentum.

Major efficiencies have already been made in the area of compound management for high throughput screening. Most of these efficiencies have been achieved with sophisticated library management systems using advanced engineering and data handling for the storage, tracking and retrieval of millions of compounds. The Automation Partnership has already provided many of the top pharmaceutical companies with modular automated storage, preparation and retrieval systems to manage compound libraries for high throughput screening. This article describes how these systems may be implemented to solve the specific problems of inventory management and reagent supply for automated chemistry.