Structures of nucleobases trapped within Au triangles and its effects on hydrogen bonding in base pairs of DNA

Mohan, P. J. ; Datta, Ayan ; Mallajosyula, Sairam S. ; Pati, Swapan K. (2006) Structures of nucleobases trapped within Au triangles and its effects on hydrogen bonding in base pairs of DNA The Journal of Physical Chemistry B, 110 (37). pp. 18661-18664. ISSN 1089-5647

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Official URL: http://pubs.acs.org/doi/abs/10.1021/jp0639041

Related URL: http://dx.doi.org/10.1021/jp0639041

Abstract

Nucleobases (adenine (A), thymine (T), cytosine (C), and guanine (G)) trapped within two metal clusters such as Au3 undergo expansion. Our investigation reveals that this primarily arises due to the concomitant increase in all the bond lengths in molecules. Such expansion of the molecules can be qualitatively understood on the basis of classical harmonic potentials in the bonds and loss of aromaticity in the rings. Specifically, the highly electronegative O and N elements in the base pairs anchor to Au atoms and form X-Au bonds, which leads to charge redistribution within the molecules. As a very important consequence of this, the nature of the hydrogen bonds (in Au3-A···T-Au3 and in Au3-G...C-Au3) change substantially within these electrodes in comparison to gas-phase structures. These hydrogen bonds have a single-well potential energy profile (of the type N···H···O and N···H···N) instead of double-well potentials (like N-H···O or N-H···N/ N···H-N types). A detailed energy calculation along the proton movement pathway supports our conclusions.

Item Type:Article
Source:Copyright of this article belongs to American Chemical Society.
ID Code:60815
Deposited On:12 Sep 2011 07:15
Last Modified:12 Sep 2011 07:15

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