Multithermal titration calorimetry: a rapid method to determine binding heat capacities.

Area of Science:

• Biophysical Chemistry
• Thermodynamics
• Biochemistry

Background:

• Isothermal Titration Calorimetry (ITC) is a standard technique for measuring binding thermodynamics.
• Determining the change in heat capacity of binding (DeltaCp) typically requires multiple experiments at different temperatures.
• Accurate DeltaCp values are crucial for understanding molecular recognition and binding events.

Purpose of the Study:

• To present a novel method, Multithermal Titration Calorimetry (MTC), for determining DeltaCp in a single experiment.
• To demonstrate the feasibility of MTC as an extension of ITC.
• To simplify and accelerate the thermodynamic characterization of binding interactions.

Main Methods:

• Extension of standard Isothermal Titration Calorimetry (ITC) equipment.
• Performing a single stepwise titration with intermediate temperature adjustments.
• Analysis of the resulting multithermal data to extract thermodynamic parameters, including DeltaCp.

Main Results:

• Successfully determined DeltaCp using the MTC method in a single experimental run.
• Validated the MTC approach using the well-characterized lysozyme-chitotriose complex.
• Demonstrated that MTC accounts for the temperature dependence of DeltaH and the binding constant.

Conclusions:

• Multithermal Titration Calorimetry (MTC) offers a streamlined approach to measure binding heat capacity.
• This method simplifies the thermodynamic analysis of molecular interactions.
• MTC provides a valuable alternative for researchers needing to determine DeltaCp efficiently.