HighPoint/CannonLab:Protein Membrane Interactions

Synopsis

Thermodynamic tools to study disordered or large biomolecular systems are well developed. High resolution structural methods can't be used on many of these systems. Osmolytes and other small solutes, combined with thermodynamic methods, have been used to probe protein and nucleic acid structural changes 1 2 3 4 5. Many protein and nucleic acid interactions with membranes resist structural characterization even at quite low resolution. We propose to develop small solutes as a tool to probe biopolymer interactions with membranes.

Stephen White and his coworkers have developed a hydrophobicity scale which predicts the free energy of transferring amino acids into lipid membranes. The structures of a series of small peptides partitioned into model membranes have been well characterized, and partition coefficients can be readily measured using fluorescence spectroscopy. We are in the process of reproducing measurements made in developing the hydrophobicity scale and perturbing the equilibria with increasing osmolyte concentrations. These data will provide a foundation for correlating structural interactions with thermodynamic measurements, and ultimately turning easily accessible thermodynamic measurements into powerful structural tools.