A protein that remembers its past: Glassy behavior in an intrinsically disordered protein

Previously, we have shown that an intrinsically disordered protein construct displays two signatures of glassy behavior, logarithmic relaxation and a Kovacs memory effect, in response to changes in applied tension. With a combination of experiments and molecular dynamics simulations, we show that this glassy behavior can be attributed to multiple, independent, and local hydrophobic patches in the disordered protein that give rise to a broad distribution of relaxation timescales. This result is unexpected given the strongly polyampholytic nature of the protein. We present a mechanism by which conformational heterogeneity creates a rich mechanical response in single polymers. This mechanism is likely to apply to other disordered proteins.