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Kinetic Screening of Nuclease Activity using Nucleic Acid Probes
Published on: November 1, 2019
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Metal Coordination to Ligand-Modified Peptide Nucleic Acid Triplexes
Dilhara R Jayarathna1, Heather D Stout1, Catalina Achim1
1Department of Chemistry , Carnegie Mellon University , 4400 Fifth Avenue , Pittsburgh , Pennsylvania 15213 , United States.
Inorganic Chemistry
|May 31, 2018
Summary
Peptide nucleic acids (PNAs) modified with ligands can organize metal ions in 3D space, creating stable, programmable nanosystems. These metal-PNA complexes enhance triplex stability, with structure dictated by metal coordination and PNA handedness.
Area of Science:
- Nanotechnology
- Supramolecular Chemistry
- Biochemistry
Background:
- Precise 3D arrangement of elements in nanosystems is a key nanotechnology challenge.
- Ligand-modified nucleic acids offer selective tools for organizing metal ions.
- Peptide nucleic acids (PNAs) can be engineered with ligands for metal coordination.
Purpose of the Study:
- To synthesize and characterize metal complexes with ligand-modified PNA triplexes.
- To investigate the role of metal coordination in PNA triplex stability.
- To explore the structural and electronic properties of these novel metal-PNA constructs.
Main Methods:
- Synthesis of PNA monomers with 2,2'-bipyridine (Bpy) or 8-hydroxyquinoline (Q) ligands.
- Formation and characterization of metal complexes with 3d metal ions (Fe2+, Cu2+, Ni2+).
- UV-vis titrations to determine stability constants.
- Electron paramagnetic resonance (EPR) and circular dichroism (CD) spectroscopy for structural analysis.
Main Results:
- Metal complexes (four- and six-coordinate) formed with Bpy- and Q-modified PNA triplexes.
- Increased thermal stability of PNA triplexes correlated with metal complex stability constants.
- EPR confirmed square planar [CuQ2] complex formation.
- Spectroscopic evidence for [MBpy3] and [MQ2] complexes, influenced by metal ion and ligand type.
- PNA triplex handedness dictates metal complex chirality.
Conclusions:
- Ligand-modified PNA triplexes serve as scaffolds for programmable metal ion organization.
- Metal complex formation enhances PNA triplex stability, tunable via metal-ligand interactions.
- The study demonstrates a method for creating structurally defined, chiral metal-PNA nanosystems.
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