Isothermal titration calorimetry and surface plasmon resonance analysis using the dynamic approach

Area of Science:

• Biophysics
• Biochemistry
• Molecular Biology

Background:

• Isothermal titration calorimetry (ITC) and surface plasmon resonance (SPR) are standard biophysical techniques for studying molecular interactions.
• Conventional analysis of ITC and SPR data often provides global binding parameters but can miss kinetic details.
• Recent advancements allow for the analysis of kinetic rate constants from ITC data by modeling instrument response.

Purpose of the Study:

• To develop and validate a dynamic approach for simulating and analyzing binding kinetics using ITC and SPR.
• To integrate dynamic instrument response modeling with binding mechanisms for various interaction models.
• To compare the accuracy of the dynamic approach with existing commercial software and experimental data.

Main Methods:

• Simulated ITC profiles for different binding site models (equivalent/independent, equivalent/sequential, aggregating systems) using a dynamic instrument response model.
• Benchmarked simulation results against the commercial software Origin-ITC.
• Analyzed experimental ITC data for 2'-CMP + RNASE and BH3I-1 + hBCLXL interactions.
• Applied the dynamic approach to simulate SPR profiles for a two-state binding model.

Main Results:

• The dynamic approach accurately reproduced simulated ITC profiles for diverse binding scenarios.
• Experimental ITC data analysis using the dynamic method yielded results comparable to conventional analysis.
• Simulated SPR profiles for a two-state model using the dynamic approach showed high accuracy against experimental data.
• The developed method provides a robust alternative for kinetic analysis of molecular interactions.

Conclusions:

• The integrated dynamic instrument response and binding mechanism modeling offers a powerful tool for detailed kinetic analysis of molecular interactions.
• This approach enhances the capabilities of ITC and SPR for characterizing complex binding events.
• The validated method provides accurate kinetic rate constants, complementing existing biophysical analysis techniques.