This proposal involves a multi-disciplinary research effort directed at studies of enzymes in folate metabolism in protozoa, in particular the bifunctional thymidylate synthase-dihydrofolate reductase (TS-DHFR). The sources to be studied are Leishmania, Trypanosoma and Plasmodium, casual agents of diseases of worldwide importance (Leishmaniasis, Trypanosomiasis and Malaria, respectively). Our objectives are aimed at obtaining fundamental biochemical information, with the belief that such knowledge will provide insight into how to assist in controlling these organisms and the diseases they cause. We will continue studies on the structure, function and inhibition of the bifunctional thymidylate synthase-dihydrofolate reductase (TS-DHFR) which is uniquely found in protozoa. We intend to express large amounts of the enzymes and study their structures and functions in detail; studies on molecular modeling and drug design will be performed. In Plasmodium falciparum, we will also prepare TS-DHFR genes from antifolate drug-resistant mutants, express the gene products in E. coli or yeast, and characterize them in detail. We will study molecular aspects of drug resistance towards antifolates to prove the molecular mechanisms of antifolate-resistance, and hopefully obtain drugs which circumvent resistance.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
5R01AI019358-13
Application #
2060916
Study Section
Medical Biochemistry Study Section (MEDB)
Project Start
1982-09-01
Project End
1997-04-30
Budget Start
1994-05-01
Budget End
1995-04-30
Support Year
13
Fiscal Year
1994
Total Cost
Indirect Cost
Name
University of California San Francisco
Department
Pharmacology
Type
Schools of Pharmacy
DUNS #
073133571
City
San Francisco
State
CA
Country
United States
Zip Code
94143
Trujillo, M; Duncan, R; Santi, D V (1997) Construction of a homodimeric dihydrofolate reductase-thymidylate synthase bifunctional enzyme. Protein Eng 10:567-73
Sirawaraporn, W; Sathitkul, T; Sirawaraporn, R et al. (1997) Antifolate-resistant mutants of Plasmodium falciparum dihydrofolate reductase. Proc Natl Acad Sci U S A 94:1124-9
Yu, P L; Zhao, J; Yu, M et al. (1996) Functional expression of the dihydrofolate reductase domain of Leishmania major dihydrofolate reductase-thymidylate synthase bifunctional protein. Protein Expr Purif 8:23-7
Prapunwattana, P; Sirawaraporn, W; Yuthavong, Y et al. (1996) Chemical synthesis of the Plasmodium falciparum dihydrofolate reductase-thymidylate synthase gene. Mol Biochem Parasitol 83:93-106
Reche, P; Arrebola, R; Santi, D V et al. (1996) Expression and characterization of the Trypanosoma cruzi dihydrofolate reductase domain. Mol Biochem Parasitol 76:175-85
Carreras, C W; Santi, D V (1995) The catalytic mechanism and structure of thymidylate synthase. Annu Rev Biochem 64:721-62
Reche, P; Arrebola, R; Olmo, A et al. (1994) Cloning and expression of the dihydrofolate reductase-thymidylate synthase gene from Trypanosoma cruzi. Mol Biochem Parasitol 65:247-58
Arrebola, R; Olmo, A; Reche, P et al. (1994) Isolation and characterization of a mutant dihydrofolate reductase-thymidylate synthase from methotrexate-resistant Leishmania cells. J Biol Chem 269:10590-6
Sirawaraporn, W; Prapunwattana, P; Sirawaraporn, R et al. (1993) The dihydrofolate reductase domain of Plasmodium falciparum thymidylate synthase-dihydrofolate reductase. Gene synthesis, expression, and anti-folate-resistant mutants. J Biol Chem 268:21637-44
Ivanetich, K M; Santi, D V (1992) 5,6-dihydropyrimidine adducts in the reactions and interactions of pyrimidines with proteins. Prog Nucleic Acid Res Mol Biol 42:127-56

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