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PubMed · 10404963

Single-molecule DNA digestion by lambda-exonuclease.

J Dapprich
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Abstract

We used a bead displacement sensor to determine the enzymatic shortening of individual molecules of unstained lambda-DNA attached to optically trapped beads. The setup has been described previously (Dapprich and Nicklaus: Bioimaging 6:25-32, 1998) and works by observing the change in position of a trapped bead depending on its viscous drag force during motion. The drag force of a naked bead increases with each attached DNA molecule to a characteristic level that depends on the length and the number of DNAs per bead. A single undigested DNA molecule on a bead will remain stable for extended periods and exhibit a constant drag force in flow. If lambda-exonuclease is added, the drag force decreases from the level for one strand of DNA on a bead to that of a naked bead in about 45 min. This result indicates that the digestion of native lambda-DNA by lambda-exonuclease occurs at an average rate of approximately 15-20 Hz.

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Bacteriophage lambdaDNA, ViralExodeoxyribonucleasesSpectrometry, FluorescenceViral ProteinsJournal Article

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J Dapprich. 1999-07-01. Single-molecule DNA digestion by lambda-exonuclease.. https://doi.org/10.1002/(sici)1097-0320(19990701)36%3A3%3C163%3A%3Aaid-cyto3%3E3.0.co%3B2-r

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