ds cDNA from antifolate-resistant Chinese hamster lung fibroblast subline DC-3F/MQ19 was ligated to Eco RI and Sal I oligonucleotide linkers and cloned into Eco RI and Sal I digested pBR322. Transformed colonies containing dihydrofolate reductase (DHFR)-specific recombinant plasmid were identified by Grunstein Hogness assay using a Chinese hamster DHFR-specific cDNA probe. A recombinant plasmid...

Pyrimethamine is a potent inhibitor of dihydrofolate reductase and is widely used in the treatment of opportunistic infections caused by the protozoan parasite Toxoplasma gondii. In order to assess the potential role of dhfr sequence polymorphisms in drug treatment failures, we examined the dhfr-ts genes of representative isolates for T. gondii virulence types I, II, and III. These strains exhi...

A series of methotrexate (MTX)-resistant human sublines developed by step increases in selected MTX concentrations have been cloned and examined for dihydrofolate reductase (DHFR) content, relative DNA copy number, and sensitivity to MTX. These cloned sublines had increased DHFR levels which were dependent on the presence of MTX in the medium. The increased levels of DHFR in the absence of MTX ...

The Lactococcus lactis gene encoding trimethoprim resistance has been cloned and expressed in Escherichia coli and Bacillus subtilis. Several lines of evidence indicate that the cloned gene encodes dihydrofolate reductase (DHFR). (i) It fully complements the fol "null" mutation in E. coli. (ii) Nucleotide sequencing of the cloned fragment revealed the presence of one open reading frame encoding...

Molecular docking is routinely used for understanding drug-receptor interaction in modern drug design. Here, we describe the docking of 2, 4-diamino-5-methyl-5-deazapteridine (DMDP) derivatives as inhibitors to human dihydrofolate reductase (DHFR). We docked 78 DMDP derivates collected from literature to DHFR and studied their specific interactions with DHFR. A new shape-based method, LigandFit...

Dihydrofolate reductase (DHFR) plays an essential role in intermediary metabolism, catalysing the NADPH-dependent reduction of dihydrofolate to tetrahydrofolate, the latter serving as a carrier of onecarbon fragments in the biosynthesis of amino acids, thymidylate and purines [ 11. DHFR has been the subject of intense investigations as it is the target of important anti-bacterial and anti-neopl...

A naturally occurring gallated polyphenol isolated from green tea leaves, (-)-epigallocatechin gallate (EGCG), has been shown to be an inhibitor of dihydrofolate reductase (DHFR) activity in vitro at concentrations found in the serum and tissues of green tea drinkers (0.1-1.0 micromol/L). These data provide the first evidence that the prophylactic effect of green tea drinking on certain forms o...

The chromosomal location of the human dihydrofolate reductase (DHFR; EC 1.5.1.3) gene that is amplified in a methotrexate-resistant human cell line has been investigated by screening a large number of human-mouse cell hybrids containing overlapping subsets of human chromosomes. A correlation of genomic blotting data with the chromosome constitution of the individual cell hybrids has allowed the...

Pteridine reductase (PTR1) is a target for drug development against Trypanosoma and Leishmania species, parasites that cause serious tropical diseases and for which therapies are inadequate. We adopted a structure-based approach to the design of novel PTR1 inhibitors based on three molecular scaffolds. A series of compounds, most newly synthesized, were identified as inhibitors with PTR1-specie...

Protozoal parasites are unusual in that their thymidylate synthase (TS) and dihydrofolate reductase (DHFR) enzymes exist on a single polypeptide. In an effort to probe the possibility of substrate channeling between the TS and DHFR active sites and to identify inhibitors specific for bifunctional TS-DHFR, we used molecular docking to screen for inhibitors targeting the shallow groove connecting...