Association of RNA with thymidylate synthase from methotrexate-resistant Streptococcus faecium.
AUTOR(ES)
Rao, K N
RESUMO
Thymidylate synthase (5,10-methylenetetrahydrofolate:dUMP C-methyltransferase, EC 2.1.1.45) from methotrexate-resistant Streptococcus faecium has a UV absorbance peak at 259 nm and stains with acridine orange because of the presence of RNA on the protein. Material having an absorbance peak at 254 nm, obtained from the enzyme by phenol extraction, is degraded by treatment with pancreatic RNase, T1 RNase, and alkali but is stable to DNase. Dowex-1 chromatography of the pure enzyme yields two polynucleotide fragments in addition to the apoenzyme. As estimated from their absorbance, these fragments contain 4 and 11 mononucleotide residues per mole of enzyme, respectively. In crude extracts, thymidylate synthase is associated with rapidly sedimenting material that is sensitive to RNase. Treatment of crude extracts with RNase, as is done routinely during thymidylate synthase purification, most likely results in the formation of the small polynucleotides found on the enzyme. The RNA is not required for enzyme activity.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=393498Documentos Relacionados
- Overproduction of a bifunctional thymidylate synthetase-dihydrofolate reductase and DNA amplification in methotrexate-resistant Leishmania tropica.
- Amino-Acid Sequence of Dihydrofolate Reductase from a Methotrexate-resistant Mutant of Streptococcus faecium and Identification of Methionine Residues at the Inhibitor Binding Site
- Isolation of the amplified dihydrofolate reductase domain from methotrexate-resistant Chinese hamster ovary cells.
- Co-existence of circular and multiple linear amplicons in methotrexate-resistant Leishmania.
- Linear amplicons as precursors of amplified circles in methotrexate-resistant Leishmania tarentolae.