PNA-DNA duplexes, triplexes, and quadruplexes are stabilized with trans-cyclopentane units

Area of Science:

• Biochemistry
• Molecular Biology
• Medicinal Chemistry

Background:

• Peptide nucleic acids (PNAs) are synthetic nucleic acid mimics with high affinity and selectivity for DNA and RNA.
• Current PNA applications are limited by the lack of predictable strategies for backbone modification to enhance binding properties.
• PNA structures include duplex, triplex, and quadruplex formations with complementary nucleic acids.

Purpose of the Study:

• To investigate the impact of incorporating (S,S)-trans-cyclopentane diamine units (tcyp) into the PNA backbone.
• To evaluate the effect of tcyp modification on the stability of various PNA-DNA structures.
• To assess the broad utility of tcyp incorporation across different PNA-oligonucleotide complex types.

Main Methods:

• Synthesis of PNA oligomers containing (S,S)-trans-cyclopentane diamine units in the backbone.
• Formation and characterization of PNA-DNA duplex, triplex, and quadruplex structures.
• Stability assessment of the modified PNA structures using biophysical techniques.

Main Results:

• Incorporation of tcyp units into the PNA backbone significantly improved the stability of PNA-DNA duplexes.
• Enhanced stability was also observed for PNA-DNA triplex and quadruplex structures containing tcyp modifications.
• The tcyp modification demonstrated broad utility, improving stability across multiple PNA-nucleic acid binding modes.

Conclusions:

• The (S,S)-trans-cyclopentane diamine modification provides a predictable strategy to enhance PNA binding stability.
• This backbone modification is effective across diverse PNA-DNA structural complexes (duplex, triplex, quadruplex).
• Tcyp-modified PNAs offer potential for improved performance in various biomedical applications requiring high-affinity nucleic acid binding.