Interaction between macrocyclic nickel complexes and the nucleotides GMP, AMP and ApG

Area of Science:

• Coordination chemistry
• Bioinorganic chemistry
• Spectroscopy

Background:

• Nickel complexes are studied for their interactions with biological molecules.
• Understanding nucleotide-metal complex interactions is crucial in bioinorganic chemistry.

Purpose of the Study:

• To investigate the reactions between specific nickel complexes (Ni(tren), Ni(cyclam), NiCR) and nucleotides (GMP, AMP, ApG).
• To compare the binding affinities and redox properties of different nickel complexes with nucleotides.
• To explore the effect of nickel oxidation state on nucleotide interactions.

Main Methods:

• 1H and 15N Nuclear Magnetic Resonance (NMR) spectroscopy
• UV spectroscopy
• Monitoring reactions in aqueous solutions

Main Results:

• Ni(tren) binds effectively to all tested nucleotides due to its pseudo-octahedral geometry.
• Ni(cyclam) and NiCR exhibit poor nucleotide binding because of steric hindrance in their square planar arrangements.
• Oxidation of Ni(cyclam) to Ni(III)(cyclam) enhances coordination, unlike NiCR.
• Ni(III)CR gradually oxidizes GMP but not AMP; Ni(III)(cyclam) shows minimal oxidation of both.
• ApG shows less efficient binding but is more readily oxidized than mononucleotides.

Conclusions:

• Nickel complex coordination geometry significantly impacts nucleotide binding.
• Oxidation state and redox potential are critical factors in nickel-nucleotide interactions and redox activity.
• Steric hindrance in square planar complexes limits nucleotide interactions.