We use the "magnetic tweezers" technique to show the structural transitions that the DNA undergoes in the force-torsion space. In particular, we focus on the regions corresponding to negative supercoiling. These regions are characterized by the formation of the so-called denaturation bubbles, which play an essential role in the replication and transcription of DNA. We experimentally map the region of the force-torsion space where the denaturation takes place. We observe that large fluctuations in DNA extension occur at one of the boundaries of this region, i.e., when the formation of denaturation bubbles and of plectonemes compete. To describe the experiments, we introduce a suitable extension of the classical model. The model correctly describes the position of the denaturation regions, the transition boundaries, and the measured values of the DNA extension fluctuations. © 2012 American Physical Society.

Salerno, D., Tempestini, A., Mai, I., Brogioli, D., Ziano, R., Cassina, V., et al. (2012). Single-Molecule Study of the DNA Denaturation Phase Transition in the Force-Torsion Space. PHYSICAL REVIEW LETTERS, 109(11) [10.1103/PhysRevLett.109.118303].

Single-Molecule Study of the DNA Denaturation Phase Transition in the Force-Torsion Space

SALERNO, DOMENICO;TEMPESTINI, ALESSIA;BROGIOLI, DORIANO COSTANTINO;ZIANO, ROBERTO;CASSINA, VALERIA;MANTEGAZZA, FRANCESCO
2012

Abstract

We use the "magnetic tweezers" technique to show the structural transitions that the DNA undergoes in the force-torsion space. In particular, we focus on the regions corresponding to negative supercoiling. These regions are characterized by the formation of the so-called denaturation bubbles, which play an essential role in the replication and transcription of DNA. We experimentally map the region of the force-torsion space where the denaturation takes place. We observe that large fluctuations in DNA extension occur at one of the boundaries of this region, i.e., when the formation of denaturation bubbles and of plectonemes compete. To describe the experiments, we introduce a suitable extension of the classical model. The model correctly describes the position of the denaturation regions, the transition boundaries, and the measured values of the DNA extension fluctuations. © 2012 American Physical Society.
Articolo in rivista - Articolo scientifico
Nanomechanics; DNA; denaturation
English
Salerno, D., Tempestini, A., Mai, I., Brogioli, D., Ziano, R., Cassina, V., et al. (2012). Single-Molecule Study of the DNA Denaturation Phase Transition in the Force-Torsion Space. PHYSICAL REVIEW LETTERS, 109(11) [10.1103/PhysRevLett.109.118303].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10281/36547
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