This contract supports the National Institute of Allergy and Infectious Diseases (NIAID) in its mission to stimulate the discovery of improved therapies of AIDS-associated opportunistic infections. While a few drugs are available to treat some of these infections, more efficacious and less toxic therapies are needed. Additionally, accepted therapies do not exist for certain opportunistic infections (OIs). In vitro assays and biochemical prescreening have been used effectively to identify structure-activity relationships (SAR) of potential new therapies. Biochemically based screening tests may be particularly useful in discovery of anti-OI drugs because: l) certain AIDS-related opportunistic pathogens cannot be cultured in vitro, 2) such assays are rapid, and more efficient for pathogens that replicate poorly in vitro, 3) enzymes critical in the replication of certain pathogens have been identified and may be exploitable therapeutically, 4) analogous host enzymes may be identified that could be used to simultaneously evaluate selectivity, and 5) development of high volume assays permits detailed SAR evaluations of compounds. Such a biochemical prescreening project has been operational at NIAID since 1988 and several promising compounds have been identified. Specifically, compounds were rationally selected from an automated data base and evaluated for inhibition of enzymes of folic acid metabolism isolated from Pneumocystis carinii, Toxoplasma gondii and host mammalian tissues. The purpose of this contract is to continue efforts to screen agents in enzymatic assays of metabolic pathways essential to the replication of AIDS-related opportunistic pathogens. Pathogens to be addressed include P. carinii, T.gondii. and Mycobacterium avium.

Project Start
1993-08-15
Project End
1996-08-14
Budget Start
1993-12-16
Budget End
1995-08-14
Support Year
Fiscal Year
1994
Total Cost
Indirect Cost
Name
Indiana University-Purdue University at Indianapolis
Department
Pharmacology
Type
Schools of Medicine
DUNS #
005436803
City
Indianapolis
State
IN
Country
United States
Zip Code
46202
Cody, Vivian; Luft, Joe R; Pangborn, Walt et al. (2004) Structure determination of tetrahydroquinazoline antifolates in complex with human and Pneumocystis carinii dihydrofolate reductase: correlations between enzyme selectivity and stereochemistry. Acta Crystallogr D Biol Crystallogr 60:646-55
Gangjee, Aleem; Adair, Ona O; Queener, Sherry F (2003) Synthesis and biological evaluation of 2,4-diamino-6-(arylaminomethyl)pyrido[2,3-d]pyrimidines as inhibitors of Pneumocystis carinii and Toxoplasma gondii dihydrofolate reductase and as antiopportunistic infection and antitumor agents. J Med Chem 46:5074-82
Cody, Vivian; Galitsky, Nikolai; Luft, Joseph R et al. (2002) Structure-based enzyme inhibitor design: modeling studies and crystal structure analysis of Pneumocystis carinii dihydrofolate reductase ternary complex with PT653 and NADPH. Acta Crystallogr D Biol Crystallogr 58:946-54
Nelson, R G; Rosowsky, A (2001) Dicyclic and tricyclic diaminopyrimidine derivatives as potent inhibitors of Cryptosporidium parvum dihydrofolate reductase: structure-activity and structure-selectivity correlations. Antimicrob Agents Chemother 45:3293-303
Cody, V; Chan, D; Galitsky, N et al. (2000) Structural studies on bioactive compounds. 30. Crystal structure and molecular modeling studies on the Pneumocystis carinii dihydrofolate reductase cofactor complex with TAB, a highly selective antifolate. Biochemistry 39:3556-64
Rosowsky, A; Papoulis, A T; Forsch, R A et al. (1999) Synthesis and antiparasitic and antitumor activity of 2, 4-diamino-6-(arylmethyl)-5,6,7,8-tetrahydroquinazoline analogues of piritrexim. J Med Chem 42:1007-17
Rosowsky, A; Cody, V; Galitsky, N et al. (1999) Structure-based design of selective inhibitors of dihydrofolate reductase: synthesis and antiparasitic activity of 2, 4-diaminopteridine analogues with a bridged diarylamine side chain. J Med Chem 42:4853-60
Rosowsky, A; Queener, S F; Cody, V (1999) Inhibition of dihydrofolate reductases from Toxoplasma gondii, Pneumocystis carinii, and rat liver by rotationally restricted analogues of pyrimethamine and metoprine. Drug Des Discov 16:25-40
Cody, V; Galitsky, N; Rak, D et al. (1999) Ligand-induced conformational changes in the crystal structures of Pneumocystis carinii dihydrofolate reductase complexes with folate and NADP+. Biochemistry 38:4303-12
Rosowsky, A; Papoulis, A T; Queener, S F (1998) 2,4-Diamino-6,7-dihydro-5H-cyclopenta[d]pyrimidine analogues of trimethoprim as inhibitors of Pneumocystis carinii and Toxoplasma gondii dihydrofolate reductase. J Med Chem 41:913-8

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