| Autor: |
Risser, Rex, Hopkins, Nancy, Davis, Ronald W., Delius, Hajo, Mulder, Carel |
| Zdroj: |
JMB Online (Journal of Molecular Biology); November 1974, Vol. 89 Issue: 4 p517,IN1,52-522,IN4,54, 475p |
| Abstrakt: |
The P1 restriction endonuclease (EcoP1) prepared from a P1 lysogen of Escherichia colimakes one double-strand break in simian virus (SV40) DNA. In the presence of cofactors S-adenosylmethionine and ATP the enzyme cleaves 70% of the closed circular SV40 DNA molecules once to produce unit-length linear molecules and renders the remaining 30% resistant to further cleavage. No molecules were found by electron microscopy or by gel electrophoresis that were cleaved more than once. It would appear that the double-strand break is made by two nearly simultaneous single-strand breaks, since no circular DNA molecules containing one single-strand break were found as intermediates during the cleavage reaction. The EcoP1 endonuclease-cleaved linear SV40 DNA molecules are not cleaved at a unique site, as shown by the generation of about 65% circular molecules after denaturation and renaturation. These EcoP1 endonuclease-cleaved, renatured circular molecules are resistant to further cleavage by EcoP1 endonuclease. |
| Databáze: |
Supplemental Index |
| Externí odkaz: |
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