Selective Assembly between Cu²⁺ and β-Nicotinamide Mononucleotide (NMN).

Area of Science:

• Coordination Chemistry
• Biochemistry
• Materials Science

Background:

• Nucleotides possess N/O coordination sites, facilitating versatile assembly with diverse metal ions.
• The interaction between nucleotides and metal ions is crucial in various biological and chemical processes.

Purpose of the Study:

• To investigate the selective assembly of β-nicotinamide mononucleotide (NMN) and its derivatives with metal ions.
• To elucidate the structural and chemical basis for selective metal ion coordination in nucleotides.

Main Methods:

• Selective precipitation experiments with NMN and various metal ions, including Cu2+.
• Comparative analysis of NMN, NMNH, NAD+, and NADH in their assembly with Cu2+.
• Isothermal titration calorimetry (ITC) to quantify binding affinities.

Main Results:

• NMN selectively assembled with Cu2+ to form a distinct blue-green precipitate.
• The reduced form, NMNH, and NADH did not exhibit similar selective precipitation with Cu2+.
• The N+ site in the pyridine moiety of NMN was identified as essential for selective Cu2+ assembly.
• ITC data indicated favorable binding of Cu2+ with NMN compared to other divalent metal ions.

Conclusions:

• The N+ site in NMN is critical for its selective coordination with Cu2+.
• A balance between electrostatic repulsion and binding affinity likely drives the selective assembly process.
• This study reveals a unique aspect of nucleotide coordination chemistry with implications for metal ion sensing and complex formation.