Toward an artificial oxidative DNA photolyase

Area of Science:

• Supramolecular Chemistry
• Organic Synthesis
• Molecular Recognition

Background:

• Cyclobutane pyrimidine dimers (CPDs) are major DNA photoproducts, and their isomers (cis,syn and trans,syn) have different biological implications.
• Selective molecular recognition of specific DNA damage isomers is crucial for understanding DNA repair mechanisms and developing therapeutic strategies.

Purpose of the Study:

• To design, synthesize, and characterize novel dioptic receptors capable of selectively binding the cis,syn cyclobutane pyrimidine dimer.
• To investigate the structural basis for selective molecular recognition and quantify binding affinities.

Main Methods:

• Design of receptors incorporating 2,6-di(acetamino)pyridine recognition units linked by triple bonds to an anthraquinone spacer.
• Convergent synthesis utilizing a modified Sonogashira reaction with zinc transmetalation.
• X-ray crystallography to determine the solid-state structure and identify intermolecular interactions.
• Binding studies to determine association constants (Ka) for target and non-target isomers.

Main Results:

• Successful synthesis and structural characterization of dioptic receptors.
• Crystal structure revealed a supramolecular 1D polymer driven by shape complementarity, pi-stacking, and hydrogen bonding.
• One receptor exhibited a selective binding affinity for the cis,syn CPD isomer with Ka = 1.0 x 10(3) M(-1).
• Binding to the trans,syn isomer was approximately one order of magnitude weaker, indicating selectivity.

Conclusions:

• The developed dioptic receptors demonstrate effective selective molecular recognition of the cis,syn cyclobutane pyrimidine dimer.
• The observed supramolecular assembly in the crystal state provides insights into the binding mechanism.
• These findings contribute to the development of tools for studying DNA damage and repair.