Microcalorimetric study of magnesium-adenosine triphosphate ternary complex

Area of Science:

• Biochemistry
• Thermodynamics
• Molecular Biology

Background:

• Magnesium-ATP (Mg-ATP) is crucial for numerous cellular processes.
• Understanding the thermodynamics of Mg-ATP complex formation is key to elucidating its biological functions.
• Previous studies focused on binary Mg-ATP complexes, leaving ternary chelates less explored.

Purpose of the Study:

• To investigate the existence and thermodynamic properties of the Mg2ATP ternary chelate.
• To compare the thermodynamic parameters of the ternary Mg2ATP complex with the binary Mg-ATP complex.
• To explore the potential regulatory role of the Mg2ATP ternary chelate in biological systems.

Main Methods:

• Utilized an original microcalorimetric method for precise thermodynamic measurements.
• Quantified the enthalpy change (ΔH) and binding constant (K) for the Mg2ATP complex.
• Compared experimental data with existing literature values for binary Mg-ATP chelates.

Main Results:

• Confirmed the existence of the Mg2ATP ternary chelate.
• Determined thermodynamic parameters: ΔH = 7.2 ± 0.5 kJ/mol and K = 49 ± 9 M⁻¹.
• Observed distinct thermodynamic values for the ternary complex compared to the binary Mg-ATP complex.

Conclusions:

• The Mg2ATP ternary chelate is a thermodynamically defined species.
• The thermodynamic characteristics suggest a specific role for this ternary complex.
• Mg2ATP may play a significant regulatory function in cellular biochemical pathways.