Effect of backbone flexibility on charge transfer rates in peptide nucleic acid duplexes.

Published

Journal Article

Charge transfer (CT) properties are compared between peptide nucleic acid structures with an aminoethylglycine backbone (aeg-PNA) and those with a γ-methylated backbone (γ-PNA). The common aeg-PNA is an achiral molecule with a flexible structure, whereas γ-PNA is a chiral molecule with a significantly more rigid structure than aeg-PNA. Electrochemical measurements show that the CT rate constant through an aeg-PNA bridging unit is twice the CT rate constant through a γ-PNA bridging unit. Theoretical calculations of PNA electronic properties, which are based on a molecular dynamics structural ensemble, reveal that the difference in the CT rate constant results from the difference in the extent of backbone fluctuations of aeg- and γ-PNA. In particular, fluctuations of the backbone affect the local electric field that broadens the energy levels of the PNA nucleobases. The greater flexibility of the aeg-PNA gives rise to more broadening, and a more frequent appearance of high-CT rate conformations than in γ-PNA.

Full Text

Duke Authors

Cited Authors

  • Wierzbinski, E; de Leon, A; Yin, X; Balaeff, A; Davis, KL; Rapireddy, S; Venkatramani, R; Keinan, S; Ly, DH; Madrid, M; Beratan, DN; Achim, C; Waldeck, DH

Published Date

  • June 2012

Published In

Volume / Issue

  • 134 / 22

Start / End Page

  • 9335 - 9342

PubMed ID

  • 22548314

Pubmed Central ID

  • 22548314

Electronic International Standard Serial Number (EISSN)

  • 1520-5126

International Standard Serial Number (ISSN)

  • 0002-7863

Digital Object Identifier (DOI)

  • 10.1021/ja301677z

Language

  • eng