Four-stranded coordination helices containing silver-adenine (purine) metallaquartets

Area of Science:

• Supramolecular Chemistry
• Coordination Chemistry
• Crystallography

Background:

• Nucleic acid quadruplexes are vital DNA and RNA structures.
• Metal-ion coordination plays a role in stabilizing nucleic acid structures.
• Adenine, a key nucleobase, can participate in metal-mediated interactions.

Purpose of the Study:

• To describe novel silver-adenine metallaquartet structures.
• To investigate the formation of these metallaquartets with modified purine frameworks.
• To understand the propensity of silver-adenine interactions in forming quartet structures.

Main Methods:

• X-ray crystallography was used to determine solid-state structures.
• Synthesis of silver-adenine complexes with modified purine derivatives.
• Analysis of coordination motifs and structural similarities to nucleic acid quadruplexes.

Main Results:

• A family of silver-adenine metallaquartets was identified, adopting a four-stranded coordination motif.
• These metallaquartets closely resemble nucleic acid quadruplexes.
• Modified purine frameworks were tolerated, yielding metallaquartets irrespective of substitution.
• All studied solid-state structures were orthorhombic, belonging to the Fdd2 space group.

Conclusions:

• Silver-adenine interactions exhibit a high propensity for forming stable quartet structures.
• The observed metallaquartets offer insights into metal-nucleobase interactions beyond natural nucleic acids.
• Structural tolerance to modified purines suggests versatility in designing such metal-organic frameworks.