The isolation and properties of a DNA-unwinding protein from Ustilago maydis
| Autor: | Ad Spanos, Geoffrey R. Banks |
|---|---|
| Rok vydání: | 1975 |
| Předmět: |
DNA Replication
DNA polymerase Ustilago DNA polymerase II DNA Single-Stranded Centrifugation Isopycnic Nucleic Acid Denaturation Chromatography Affinity Fungal Proteins chemistry.chemical_compound Structural Biology Animals A-DNA Molecular Biology Replication protein A Deoxyribonucleases DNA clamp biology DNA synthesis Basidiomycota DNA biology.organism_classification Molecular biology Stimulation Chemical Molecular Weight chemistry DNA Nucleotidyltransferases DNA Viral Nucleic Acid Renaturation biology.protein Electrophoresis Polyacrylamide Gel Protein Binding |
| Zdroj: | Journal of Molecular Biology. 93:63-77 |
| ISSN: | 0022-2836 |
| Popis: | Mitotic cells of the eukaryote Ustilago maydis contain a DNA-unwinding protein. It has been purified to apparent homogeneity and it possesses many of the properties of the prokaryotic DNA-unwinding proteins. It has a molecular weight of 20,000, binds tightly and specifically to single-stranded DNA and catalyses its renaturation at physiological temperatures. It also denatures double-stranded DNA, reducing the melting temperature of poly[d(A-T)] · [d(A-T)] by almost 50 deg. C. One molecule of the protein apparently binds to not more than seven to ten single-stranded DNA nucleotides and there is evidence that the binding may be co-operative. It stimulates the initial rate of DNA synthesis by the Ustilago DNA polymerase when the latter repairs partially single-stranded DNA templates. Conversely, it inhibits the degradation of double-stranded DNA by Escherichia coli exonuclease III and that of single-stranded DNA by U. maydis DNAase I. One cell of U. maydis contains 2.5 to 3.0 × 105 molecules of the protein, a number that may suggest a structural rather than a catalytic role. |
| Databáze: | OpenAIRE |
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