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Single-Molecule Analysis of Sf9 Purified Superprocessive Kinesin-3 Family Motors
Published on: July 27, 2022
DNA transport into Bacillus subtilis requires proton motive force to generate large molecular forces
Berenike Maier1, Ines Chen, David Dubnau
1Department of Biological Sciences, Columbia University, 1212 Amsterdam Ave., New York, New York 10027, USA. Berenike.Maier@physik.lmu.de
Abstract:
Bacteria can acquire genetic diversity, including antibiotic resistance and virulence traits, by horizontal gene transfer. In particular, many bacteria are naturally competent for uptake of naked DNA from the environment in a process called transformation. Here, we used optical tweezers to demonstrate that the DNA transport machinery in Bacillus subtilis is a force-generating motor. Single DNA molecules were processively transported in a linear fashion without observable pausing events. Uncouplers inhibited DNA uptake immediately, suggesting that the transmembrane proton motive force is needed for DNA translocation. We found an uptake rate of 80 +/- 10 bp s(-1) that was force-independent at external forces <40 pN, indicating that a powerful molecular machine supports DNA transport.
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