Functional Design and Biophysical Characterization of Analyte-Responsive Polymers.

Area of Science:

• Biomaterials Science
• Polymer Chemistry
• Protein Engineering

Background:

• Analyte-responsive polymers (ARPs) are crucial for advanced biosensing applications.
• Elastin-like polymers (ELPs) are intrinsically disordered polymers with tunable phase behavior.
• Understanding ligand-induced changes in ELP dynamics and assembly is key for developing responsive materials.

Purpose of the Study:

• To demonstrate proof-of-concept for analyte-responsive polymers (ARPs) in biosensing.
• To investigate the impact of ligand binding on the temperature-dependent dynamics and self-assembly of ELP-SH3 fusion proteins.
• To characterize the thermodynamic and structural changes associated with SH3 binding to ELP.

Main Methods:

• Isothermal titration calorimetry (ITC) for binding thermodynamics.
• Circular dichroism (CD) spectroscopy for conformational analysis.
• Dynamic light scattering (DLS) and temperature-dependent UV-vis spectroscopy for phase behavior and assembly studies.

Main Results:

• SH3 protein binding increased the transition temperature of the ELP-SH3 fusion protein.
• Ligand binding was observed to destabilize ARP assemblies.
• The observed changes were consistent with theoretical models for ELP fusions and reproducible in complex media.

Conclusions:

• Ligand binding can specifically trigger responses in analyte-responsive polymers.
• The interdependence of ligand binding and phase behavior in intrinsically disordered protein systems is highlighted.
• This work provides a foundation for designing sophisticated biosensing materials based on polymer-protein conjugates.