Nucleotide sequence of dihydrofolate reductase type VI

Characterization of a R plasmid-associated, trimethoprim-resistant dihydrofolate reductase and determination of the nucleotide sequence of the reductase gene.

The trimethoprim-resistant dihydrofolate reductase associated with the R plasmid R388 was isolated from strains that over-produce the enzyme. It was purified to apparent homogeneity by affinity chromatography and two consecutive gel filtration steps under native and denaturing conditions. The purified enzyme is composed of four identical subunits with molecular weights of 8300. A 1100 bp long D...

Dihydrofolate reductase: partial sequence of the Lactobacillus casei enzyme and homology with other dihydrofolate reductases [proceedings].

Lactobacillus casei dihydrofolate reductase

1 The binding of a series of amide derivatives of methotrexate to Lactobacillus casei dihydrofolate reductase has been studied by inhibition constant measurements and by 'H n.m.r. spectroscopy. 2 Amide modification of the a-carboxylate of methotrexate was found to prevent interaction of the y-carboxylate with the imidazole of His 28. 3 Estimates of the contributions to the binding energy from t...

Tales of Dihydrofolate Binding to R67 Dihydrofolate Reductase

Homotetrameric R67 dihydrofolate reductase possesses 222 symmetry and a single active site pore. This situation results in a promiscuous binding site that accommodates either the substrate, dihydrofolate (DHF), or the cofactor, NADPH. NADPH interacts more directly with the protein as it is larger than the substrate. In contrast, the p-aminobenzoyl-glutamate tail of DHF, as monitored by nuclear ...

Dihydrofolate reductase from Neisseria sp.

Members of the genus Neisseria are relatively nonsusceptible to trimethoprim, an inhibitor of dihydrofolate reductase. For example, the minimal inhibitory concentration (MIC) of trimethoprim for N. gonorrhoeae ranges from 2 to 70 mug/ml, whereas the MIC for Escherichia coli is 0.2 mug/ml or less. In an effort to understand this difference, dihydrofolate reductase was partially purified from fiv...