1pnn

Publication Abstract from PubMed

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.

A nucleic acid triple helix formed by a peptide nucleic acid-DNA complex.,Betts L, Josey JA, Veal JM, Jordan SR Science. 1995 Dec 15;270(5243):1838-41. PMID:8525381^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.