Ternary Phase Diagrams of Viral Proteins: The Example of H1N1 Influenza

The proteins encoded by a biological system present a curious mix of properties. On the one hand, the molecules are tasked with different functions: the system practices and depends critically on the division of labor. On the other hand, the proteins operate cooperatively: the tasks of one are complemented and, in multiple cases, brought to completion by another. How else could the system survive over the long term? The mix of diverse and cooperative traits can be explored with the help of thermodynamic tools. The variables of state for proteins can be coarse-grained so as to place points on phase diagrams. Variables which place points close to one another shine light on the cooperative facets of systems. Variables which disperse points shed light on the diversity of functions. There is one phase point for each protein so encoded and a proteome confers a locus of points. Here we illustrate a novel diagrammatic technique applied to viral systems, specifically influenza A. The motivation is to screen and identify the sites of proteins most critical to the cooperative and complementary nature. Such sites should be targeted for mutation or inhibition to attenuate the impact on host populations.