PNA versus DNA: effects of structural fluctuations on electronic structure and hole-transport mechanisms.

Published

Journal Article

The effects of structural fluctuations on charge transfer in double-stranded DNA and peptide nucleic acid (PNA) are investigated. A palindromic sequence with two guanine bases that play the roles of hole donor and acceptor, separated by a bridge of two adenine bases, was analyzed using combined molecular dynamics (MD) and quantum-chemical methods. Surprisingly, electronic structure calculations on individual MD snapshots show significant frontier orbital electronic population on the bridge in approximately 10% of the structures. Electron-density delocalization to the bridge is found to be gated by fluctuations of the covalent conjugated bond structure of the aromatic rings of the nucleic bases. It is concluded, therefore, that both thermal hopping and superexchange should contribute significantly to charge transfer even in short DNA/PNA fragments. PNA is found to be more flexible than DNA, and this flexibility is predicted to produce larger rates of charge transfer.

Full Text

Duke Authors

Cited Authors

  • Hatcher, E; Balaeff, A; Keinan, S; Venkatramani, R; Beratan, DN

Published Date

  • September 2008

Published In

Volume / Issue

  • 130 / 35

Start / End Page

  • 11752 - 11761

PubMed ID

  • 18693722

Pubmed Central ID

  • 18693722

Electronic International Standard Serial Number (EISSN)

  • 1520-5126

International Standard Serial Number (ISSN)

  • 0002-7863

Digital Object Identifier (DOI)

  • 10.1021/ja802541e

Language

  • eng