- Elings 1601
- Soft and Living Matter Seminar Series
Proteins retain function when attached to some surfaces (e.g., the cell membrane) and yet often unfold and inactivate when attached to others (e.g., the artificial surfaces used in many technologies). Our understanding of why these effects occur, however, has been hampered by a lack of quantitative experimental methods by which we can measure the thermodynamics of biomolecule-surface interactions. That is, despite a large body of qualitative literature describing how adsorption alters protein structure, and a large number of empirical studies searching for adsorption-resistant surfaces, quantitative, experimentally testable insights into how and why proteins unfold on some surfaces and not others have proven elusive. In response, we have developed a new experimental (electrochemical) approach for measuring the folding free energy of biomolecules site-specifically attached to well-defined, macroscopic surfaces (i.e., flat at the molecular length scale). Comparison with bulk-solution-phase folding free energies then informs on the thermodynamics of the biomolecule’s interactions with the surface and, in turn, the mechanisms that drive them. Using this novel approach we have, for the first time, accurately measured the free energy with which a simple biomolecule interacts with a set of chemically distinct macroscopic surfaces. In parallel, we have also developed a simple, first-principles theory that recovers our key experimental observations quantitatively, providing molecular details unavailable to experiment alone.