title: DNA-like double helix formed by peptide nucleic acid.
abstract: Although the importance of the nucleobases in the DNA double helix is well understood, the evolutionary significance of the deoxyribose phosphate backbone and the contribution of this chemical entity to the overall helical structure and stability of the double helix is not so clear. Peptide nucleic acid (PNA) is a DNA analogue with a backbone consisting of N-(2-aminoethyl)glycine units (Fig. 1) which has been shown to mimic DNA in forming Watson-Crick complementary duplexes with normal DNA. Using circular dichroism spectroscopy we show here that two complementary PNA strands can hybridize to one another to form a helical duplex. There is a seeding of preferred chirality which is induced by the presence of an L- (or D-) lysine residue attached at the carboxy terminus of the PNA strand. These results indicate that a (deoxy)ribose phosphate backbone is not an essential requirement for the formation of double helical DNA-like structures in solution.
authors.affiliation: Department of Physical Chemistry, Chalmers University of Technology, Gothenburg, Sweden.
authors.forename: P
authors.initials: P
authors.lastname: Wittung
authors.forename: P E
authors.initials: PE
authors.lastname: Nielsen
authors.forename: O
authors.initials: O
authors.lastname: Buchardt
authors.forename: M
authors.initials: M
authors.lastname: Egholm
authors.forename: B
authors.initials: B
authors.lastname: Nordén
mesh_terms: D001483:Base Sequence; D002942:Circular Dichroism; D004247:DNA / Q000737:chemistry*; D005998:Glycine / Q000031:analogs & derivatives / Q000737:chemistry; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D009693:Nucleic Acid Hybridization; D009838:Oligodeoxyribonucleotides / Q000737:chemistry*; D020135:Peptide Nucleic Acids
chemical_list: D009838:Oligodeoxyribonucleotides; D020135:Peptide Nucleic Acids; C078138:peptide nucleic acid, T10-lysine; C028791:N-(2-aminoethyl)glycine; D004247:DNA; D005998:Glycine