Please use this identifier to cite or link to this item: http://hdl.handle.net/2445/98168
Title: Mechanism of strand displacement synthesis by DNA replicative polymerases
Author: Mañosas Castejón, María
Spiering, Michelle M.
Ding, Fangyuan
Bensimon, David
Allemand, Jean-François
Benkovic, Stephen J.
Croquette, Vincent
Keywords: ADN
Polimerització
DNA
Polymerization
Issue Date: 2012
Publisher: Oxford University Press
Abstract: Replicative holoenzymes exhibit rapid and processive primer extension DNA synthesis, but inefficient strand displacement DNA synthesis. We investigated the bacteriophage T4 and T7 holoenzymes primer extension activity and strand displacement activity on a DNA hairpin substrate manipulated by a magnetic trap. Holoenzyme primer extension activity is moderately hindered by the applied force. In contrast, the strand displacement activity is strongly stimulated by the applied force; DNA polymerization is favoured at high force, while a processive exonuclease activity is triggered at low force. We propose that the DNA fork upstream of the holoenzyme generates a regression pressure which inhibits the polymerization-driven forward motion of the holoenzyme. The inhibition is generated by the distortion of the template strand within the polymerization active site thereby shifting the equilibrium to a DNA-protein exonuclease conformation. We conclude that stalling of the holoenzyme induced by the fork regression pressure is the basis for the inefficient strand displacement synthesis characteristic of replicative polymerases. The resulting processive exonuclease activity may be relevant in replisome disassembly to reset a stalled replication fork to a symmetrical situation. Our findings offer interesting applications for single-molecule DNA sequencing.
Note: Reproducció del document publicat a: http://dx.doi.org/10.1093/nar/gks253
It is part of: Nucleic Acids Research, 2012, vol. 40, num. 13, p. 6174-6186
Related resource: http://dx.doi.org/10.1093/nar/gks253
URI: http://hdl.handle.net/2445/98168
ISSN: 0305-1048
Appears in Collections:Articles publicats en revistes (Física de la Matèria Condensada)

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