Dramatic changes in DNA conductance with stretching: structural polymorphism at a critical extension

Bag, Saientan and Mogurampelly, Santosh and Goddard, William A and Maiti, Prabal K (2016) Dramatic changes in DNA conductance with stretching: structural polymorphism at a critical extension. In: NANOSCALE, 8 (35). pp. 16044-16052.

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Abstract

In order to interpret recent experimental studies of the dependence of conductance of ds-DNA as the DNA is pulled from the 3'end1-3'end2 ends, which find a sharp conductance jump for a very short (4.5%) stretching length, we carried out multiscale modeling to predict the conductance of dsDNA as it is mechanically stretched to promote various structural polymorphisms. We calculate the current along the stretched DNA using a combination of molecular dynamics simulations, non-equilibrium pulling simulations, quantum mechanics calculations, and kinetic Monte Carlo simulations. For 5'end1-5'end2 attachments we find an abrupt jump in the current within a very short stretching length (6 angstrom or 17%) leading to a melted DNA state. In contrast, for 3'end1-3'end2 pulling it takes almost 32 angstrom (84%) of stretching to cause a similar jump in the current. Thus, we demonstrate that charge transport in DNA can occur over stretching lengths of several nanometers. We find that this unexpected behaviour in the B to S conformational DNA transition arises from highly inclined base pair geometries that result from this pulling protocol. We found that the dramatically different conductance behaviors for two different pulling protocols arise from how the hydrogen bonds of DNA base pairs break.

Item Type:	Journal Article
Publication:	NANOSCALE
Additional Information:	Copy right for this article belongs to the ROYAL SOC CHEMISTRY, THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND
Department/Centre:	Division of Physical & Mathematical Sciences > Physics
Date Deposited:	22 Oct 2016 09:46
Last Modified:	22 Oct 2016 09:46
URI:	http://eprints.iisc.ac.in/id/eprint/55074

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