Conformational Changes in Surface-Immobilized Proteins Measured Using Combined Atomic Force and Fluorescence...

Area of Science:

• Biophysics
• Protein Dynamics
• Nanotechnology

Background:

• Protein functions are driven by physical motions (conformational changes) within a free-energy landscape.
• Understanding protein dynamics, including equilibrium and nonequilibrium motions, is crucial for elucidating biological functions.
• Key parameters like energy landscapes, barriers, and external influences on protein states remain largely unknown.

Purpose of the Study:

• To develop a novel multimolecule approach for precise protein immobilization and study.
• To investigate the fundamental dynamical parameters of proteins, including stiffness and conformational transitions.
• To connect protein dynamics to biological function through experimental measurements.

Main Methods:

• Utilized an atomic force microscope (AFM)-based nanografting technique for controlled protein immobilization on gold substrates.
• Created self-assembled, biologically active protein ensembles (protein patches) with defined locations and orientations.
• Performed AFM-force compression and fluorescence experiments on the engineered protein patches.

Main Results:

• Successfully controlled protein location and orientation on substrates, forming well-defined protein patches.
• Measured fundamental dynamical parameters: protein stiffness, elastic modulus, and transition energies between conformational states.
• Provided new experimental data on the processes governing protein dynamics and their link to function.

Conclusions:

• The nanografting and AFM approach offers precise control over protein arrangement for advanced biophysical studies.
• The study yields critical insights into protein mechanical properties and energy landscapes.
• This work advances the understanding of how protein dynamics dictate biological activity.