Lactobacillus casei dihydrofolate reductase
نویسندگان
چکیده
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 the ac-carboxylate-Arg 57 and y-carboxylate-His 28 interactions have been made from a combination of inhibition and n.m.r. data.
منابع مشابه
Characterization of the DNA binding region recognized by dihydrofolate reductase from lactobacillus casei.
Two specific DNA binding sites for the enzyme dihydrofolate reductase from Lactobacillus casei have been located by means of an immunoprecipitation assay within a 2900-base pair L. casei DNA fragment containing the L. casei dihydrofolate reductase structural gene, which was previously cloned into pBR322. The inserted L. casei DNA was mapped using restriction endonucleases, and the location and ...
متن کاملDihydrofolate reductase: partial sequence of the Lactobacillus casei enzyme and homology with other dihydrofolate reductases [proceedings].
متن کامل
DNA binding by dihydrofolate reductase from Lactobacillus casei.
The protein-dependent retention of double-stranded DNA molecules on nitrocellulose filters has been used to show that pure dihydrofolate reductase from Lactobacillus casei has affinity for DNA. Dihydrofolate reductase will bind to end-labeled linear double-stranded DNA and to DNA in supercoiled form. Coenzymes and certain inhibitors do not affect the affinity of the protein to DNA, indicating t...
متن کاملDihydrofolate Reductase from Amethopterin-resistant Lactobacillus casei SEQUENCES OF THE CYANOGEN BROMIDE PEPTIDES AND COMPLETE SEQUENCE OF THE ENZYME*
The complete amino acid sequence of dihydrofolate reductase from an amethopterin-resistant strain of Lactobacillus casei has been determined by sequence analysis of peptides produced by cleavage with cyanogen bromide, trypsin, staphylococcal protease, and myxobatter protease. Comparison of this sequence with those of reductases from other bacterial sources shows that the enzymes are homologous....
متن کاملDihydrofolate reductase from amethopterin-resistant Lactobacillus casei. Sequences of the cyanogen bromide peptides and complete sequences of the enzyme.
The complete amino acid sequence of dihydrofolate reductase from an amethopterin-resistant strain of Lactobacillus casei has been determined by sequence analysis of peptides produced by cleavage with cyanogen bromide, trypsin, staphylococcal protease, and myxobacter protease. Comparison of this sequence with those of reductases from other bacterial sources shows that the enzymes are homologous....
متن کامل