A Stickiness Scale for Disordered Proteins

Disordered proteins are a heterogeneous group of proteins that play a broad range of functions in biology and display conformational properties ranging from compact globules to expanded chains. Here we describe the results of a data-driven approach to derive a scale that represents the propensity of the 20 amino acids to interact with one another relative to water. The scale is based on biophysical experiments on 115 proteins and can be thought of as a "stickiness" (or hydropathy) scale for disordered proteins. We compare the scale to 70 other previously reported hydropathy scales and find that it is closer to four scales related to membrane proteins or the transition temperatures of elastin-like peptides. We illustrate how the scale may be useful to quantify the role of sequence composition and patterning in disordered proteins, and we expect that it may also be used to understand the driving forces for their interactions with other molecules and their evolutionary conservation.