Abstract

Membrane proteins regulate a large number of cellular functions, and have great potential as tools for manipulation of biological systems. Developing these tools requires a robust and quantitative understanding of membrane protein folding and interactions within the bilayer. Over the last 10 years, we have used a wide range of biophysical and biochemical tools to better understand the rules of engagement for native protein sequences in membranes and membrane mimetics. From these studies, and similar studies in labs across the world, a link between transmembrane domain sequence “motifs” and protein-protein interaction propensity has emerged. We have utilized this information to design a series of proteins to probe the net thermodynamic contribution of well-known sequence motifs to transmembrane helix-helix association in a biological membrane. We have quantified the apparent free energy contribution of a range of motifs to transmembrane helix self-association in a biological membrane, and our initial results suggest that the free energy barrier to overcoming weak association is quite small. This work has allowed us to rationalize the contribution of key motifs to transmembrane helix association, and offers a route to direct the design of novel sequences for use in biotechnology or synthetic biology.