Crystal structure of a peptide nucleic acid (PNA) duplex at 1.7 A resolution

The crystal structure of a PNA duplex reveals both a right- and a left-handed helix in the unit cell. The helices are wide (28A), large pitched (18bp) with the base pairs perpendicular to the helix axis, thereby demonstrating that PNA besides adapting to oligonucleotide partners also has a unique structure by itself.