title: Quadruplex formation by a guanine-rich PNA oligomer.
abstract: A guanine-rich PNA dodecamer having the sequence H-G4T4G4-Lys-NH2 (G-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.
authors.affiliation: Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213-3890, USA.
authors.forename: Bhaskar
authors.initials: B
authors.lastname: Datta
authors.forename: Mark E
authors.initials: ME
authors.lastname: Bier
authors.forename: Subhadeep
authors.initials: S
authors.lastname: Roy
authors.forename: Bruce A
authors.initials: BA
authors.lastname: Armitage
mesh_terms: D001483:Base Sequence; D004247:DNA / Q000737:chemistry*; D054856:G-Quadruplexes; D006147:Guanine / Q000737:chemistry*; D009690:Nucleic Acid Conformation; D009693:Nucleic Acid Hybridization; D020135:Peptide Nucleic Acids / Q000737:chemistry*; D013050:Spectrometry, Fluorescence; D021241:Spectrometry, Mass, Electrospray Ionization; D013056:Spectrophotometry, Ultraviolet
chemical_list: D020135:Peptide Nucleic Acids; D006147:Guanine; D004247:DNA