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Article

Quadruplex Formation by a Guanine-Rich PNA Oligomer

Supporting Info

Bhaskar Datta, Mark E. Bier, Subhadeep Roy, and Bruce A. Armitage*

Contribution from the Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213-3890

J. Am. Chem. Soc., 2005, 127 (12), pp 4199–4207

DOI: 10.1021/ja0446202

Publication Date (Web): March 5, 2005

In papers with more than one author, the asterisk indicates the name of the author to whom inquiries about the paper should be addressed.

army@cyrus.andrew.cmu.edu

Abstract

A guanine-rich PNA dodecamer having the sequence H-G₄T₄G₄-Lys-NH₂ (G₄-PNA) hybridizes with a DNA dodecamer of homologous sequence to form a four-stranded quadruplex (Datta, B.; Schmitt, C.; Armitage, B. A. J. Am. Chem. Soc. 2003, 125, 4111−4118). This report describes quadruplex formation by the PNA alone. UV melting curves and fluorescence resonance energy transfer experiments reveal formation of a multistranded structure stabilized by guanine tetrads. The ion dependency of these structures is analogous to that reported for DNA quadruplexes. Electrospray ionization mass spectrometry indicates that both dimeric and tetrameric quadruplexes are formed by G₄-PNA, with the dimeric form being preferred. These results have implications for the use of G-rich PNA for homologous hybridization to G-rich targets in chromosomal DNA and suggest additional applications in assembling quadruplex structures within lipid bilayer environments.