Duplex formation and secondary structure of {\gamma}-PNA observed by NMR and CD

TL;DR

This study uses NMR and CD to investigate the duplex formation and secondary structures of gamma-PNA, revealing stable duplexes with high melting temperatures influenced by backbone chirality.

Contribution

It provides new insights into the structural properties and stability of gamma-PNA duplexes, including effects of backbone chirality, using NMR and CD techniques.

Findings

Gamma-PNA duplexes form standard and non-standard base pairs.

Duplexes exhibit high melting transition temperatures.

Chiral backbone enhances duplex stability.

Abstract

Peptide Nucleic Acids (PNA) are non-natural oligonucleotides mimics. {\gamma}-PNA backbone are formed by standard nucleic acids nucleobases connected by a neutral N-(2-aminoethyl)glycine backbone linked by a peptide bond. In this study, we use Nuclear Magnetic Resonance (NMR) and Circular Dichroism (CD) to explore the properties of the supramolecular duplexes formed by these species. We show that standard Watson-Crick base pair as well as non-standard ones are formed in solution. The duplexes thus formed present marked melting transition temperatures substantially higher than their nucleic acid homologs. Moreover, the presence of a chiral group on the {\gamma}-peptidic backbone increases further more this transition temperature, leading to very stable duplexes.