Bis-naphthalene diimide exhibiting an effective bis-threading intercalating ability

Area of Science:

• Supramolecular Chemistry
• Molecular Biology
• Organic Synthesis

Background:

• Naphthalene diimide (NDI) derivatives are known for their electronic properties and potential in molecular recognition.
• Understanding DNA-binding mechanisms is crucial for developing novel therapeutic and diagnostic agents.
• Automated peptide synthesis offers a robust platform for constructing complex molecules with specific functionalities.

Purpose of the Study:

• To synthesize and characterize a novel bis-naphthalene diimide molecule (1).
• To investigate the DNA-binding mode and affinity of compound 1.
• To elucidate the molecular interactions governing the binding of compound 1 to double-stranded DNA (dsDNA).

Main Methods:

• Automated peptide synthesis using Fmoc-Lys(Boc)-OH and Fmoc-Lys(NDI)-OH.
• Absorption spectroscopy to study intramolecular stacking.
• Viscometric titration to assess DNA binding and mode.
• Kinetic studies to determine binding affinity.

Main Results:

• Successful synthesis of bis-naphthalene diimide (1).
• Spectroscopic evidence for intramolecular stacking of NDI units in solution.
• Viscometric and kinetic data indicate "bis-threading intercalation" into dsDNA.
• High affinity constant (K = 10^6 M^-1) for dsDNA binding via bis-threading intercalation.

Conclusions:

• Compound 1 exhibits a unique "bis-threading intercalation" binding mode with dsDNA.
• The binding is driven by the NDI moieties, not electrostatic interactions of the lysine residues.
• This molecule represents a promising scaffold for DNA-interactive agents with high affinity and specificity.