Studying How Artificial Surfaces Affect Proteins and Nucleic Acids

Biomolecules frequently unfold on and irreversibly stick to the surfaces of surgical implants or biosensors. This biomolecular buildup can compromise the function and biocompatibility of the material. Although we know of manmade materials on which biomolecules retain their structure and function, the physics of why they do so on these specific surfaces and not on others are not understood. By improving our understanding of folding thermodynamics we are closer to minimizing surface induced misfolding of biomolecules. This will facilitate the design of new biocompatible materials. I have optimized a new technique for measuring how proteins and nucleic acids fold and function on surfaces. I used this technique to study the folding of a DNA stem loop both in solution by spectroscopy and on surfaces using electrochemistry. I successfully measured how surface-confinement affects the folding of a DNA stem loop, and found that the stem loop structure is less stable on our test surface than it is in solution. Further, I used genetically engineered bacteria to produce large quantities of nine different protein variants to be used for protein folding experiments on surfaces.  I purified these proteins with liquid chromatography and analyzed their purity by gel electrophoresis and mass spectrometry. While additional experiments are needed to fully adapt this approach to proteins, my work represents a significant step toward this goal.