Characterization of an R-plasmid dihydrofolate reductase with a monomeric structure.
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منابع مشابه
Characterization of an R-plasmid dihydrofolate reductase with a monomeric structure.
A plasmid-encoded dihydrofolate reductase that originated in a clinical isolate of Salmonella typhimurium (phage type 179) moderately resistant to trimethoprim has been isolated and characterized. The dihydrofolate reductase (called type III) was purified to homogeneity using a combination of gel filtration, hydrophobic chromatography, and methotrexate affinity chromatography. Polyacrylamide ge...
متن کاملCharacterization 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...
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In recent years resistance to the antibacterial agent trimethoprim (Tmp) has become more widespread, and several trimethoprim-resistant (Tmpr) dihydrofolate reductases (DHFRs) have been described from gram-negative bacteria. In staphylococci, only one Tmpr DHFR has been described, the type S1 DHFR, which is encoded by the dfrA gene found on transposon Tn4003. In order to investigate the coincid...
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The structure of chicken liver dihydrofolate reductase (5,6,7,8-tetrahydrofolate:NADP+ oxidoreductase (EC 1.5.1.3)), in a ternary complex with NADPH and a phenyltriazine inhibitor, has been determined at a nominal resolution of 2.9 A. Overall backbone chain folding is very similar to that observed in Escherichia coli and Lactobacillus casei dihydrofolate reductases. About 70% of the additional ...
متن کاملIdentification of the type I trimethoprim-resistant dihydrofolate reductase specified by the Escherichia coli R-plasmid R483: comparison with procaryotic and eucaryotic dihydrofolate reductases.
We have isolated and determined the nucleotide sequence of a 1,626-base-pair fragment from R-plasmid R483 which encodes a trimethoprim-resistant dihydrofolate reductase. Analysis of the nucleotide sequence of this fragment revealed the presence of two open reading frames, each sufficient to encode polypeptides of approximately 17,000 daltons. Both open regions are preceded by sequences conformi...
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ژورنال
عنوان ژورنال: Journal of Biological Chemistry
سال: 1984
ISSN: 0021-9258
DOI: 10.1016/s0021-9258(18)91094-x