Aza-PNA: Engineering E-Rotamer Selectivity Directed by Intramolecular H-bonding.

The replacement of α(CH2) by NH in monomers of standard aeg PNA and its homologue ß-ala PNA leads to respective aza-PNA monomers (1 and 2) in which the NαH can form either an 8-membered H-bonded ring with folding of the backbone (DMSO and water) or a 5-membered NαH─αCO (water) to stabilize E-type rotamers. Such aza-PNA oligomers with exclusive E rotamers and intraresidue backbone H-bonding can modulate its DNA/RNA binding and assembling properties.