A nucleic acid triple helix formed by a peptide nucleic acid-DNA complex.
The crystal structure of a nucleic acid triplex reveals a helix, designated P-form, that differs from previously reported nucleic acid structures. The triplex consists of one polypurine DNA strand complexed to a polypyrimidine hairpin peptide nucleic acid (PNA) and was successfully designed to promote Watson-Crick and Hoogsteen base pairing. The P-form helix is underwound, with a base tilt similar to B-form DNA. The bases are displaced from the helix axis even more than in A-form DNA. Hydrogen bonds between the DNA backbone and the Hoogsteen PNA backbone explain the observation that polypyrimidine PNA sequences form highly stable 2:1 PNA-DNA complexes. This structure expands the number of known stable helical forms that nucleic acids can adopt.
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Glaxo Wellcome, Research Triangle Park, NC 27709, USA.
Josey
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Veal
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Jordan
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D000595:Amino Acid Sequence; D001483:Base Sequence; D018360:Crystallography, X-Ray; D004247:DNA / Q000737:chemistry*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D009838:Oligodeoxyribonucleotides / Q000737:chemistry; D009842:Oligopeptides / Q000737:chemistry*; D011487:Protein Conformation
D009838:Oligodeoxyribonucleotides; D009842:Oligopeptides; D004247:DNA