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Original Article
Single-molecule DNA digestion by lambda-exonuclease
Article first published online: 15 JUN 1999
DOI: 10.1002/(SICI)1097-0320(19990701)36:3<163::AID-CYTO3>3.0.CO;2-R
Copyright © 1999 Wiley-Liss, Inc.
Issue
1552-4930/asset/cover.gif?v=1&s=3df33f34517aaa739d7876df137e2ab92c5f82e7 "Cytometry")
Cytometry
Special Issue: Single Molecule Detection and Ultrasensitive Analysis in the Life Sciences
Volume 36, Issue 3, pages 163–168, 1 July 1999
Additional Information
How to Cite
Dapprich, J. (1999), Single-molecule DNA digestion by lambda-exonuclease. Cytometry, 36: 163–168. doi: 10.1002/(SICI)1097-0320(19990701)36:3<163::AID-CYTO3>3.0.CO;2-R
Publication History
- Issue published online: 15 JUN 1999
- Article first published online: 15 JUN 1999
- Manuscript Accepted: 11 DEC 1998
- Manuscript Received: 14 OCT 1998
- Abstract
- References
- Cited By
Keywords:
- lambda-exonuclease;
- optical trap;
- bead displacement;
- single-molecule DNA sequencing
Abstract
We used a bead displacement sensor to determine the enzymatic shortening of individual molecules of unstained λ-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 λ-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 λ-DNA by λ-exonuclease occurs at an average rate of approximately 15–20 Hz. Cytometry 36:163–168, 1999. © 1999 Wiley-Liss, Inc.