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Direct Observation of Enzymes Replicating DNA Using a Single-molecule DNA Stretching Assay
Published on: March 23, 2010
The assay and isolation of DNA rings using an ATP-dependent endonuclease
Abstract:
The ATP-dependent endonuclease from Hemophilus influenzae is relatively inactive on closed or open DNA rings, yet rapidly hydrolyzes single- or double-chained linear DNA. This enzyme in combination with an exonuclease (exo VII) has been shown to spare various circular DNA molecules including those having single-chain regions of significant length. However, rings containing single-chained regions are broken at a rate depending on the length of these regions. By admixing a linear DNA of alternate radiolabel, a simple assay for DNA rings has been developed. The application of this procedure to the assay of folded rings from Drosophila DNA is demonstrated.
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