Figure 3. Temperature- versus force-induced unjamming.

Peak disappearance upon temperature and force unfolding for the three proteins studied. Semi-log plot of force distribution P_nb(f_nb) for non-bonding interactions against scaled force f_nb. Variation of P_nb(f_nb) under different Ts shown in a,c,e, and under different F^ext in b,d,f for titin (a,b), ubiquitin (c,d) and calmodulin (e,f). For high F^ext forces (that is, beyond unfolding, for example, green curve in Fig. 3b), note the additional ‘ripples' appearing for small f_nb in accord with data on triangular lattices under increasing anisotropy of shear (cf., for example, Fig. 5 in ref. 46 and references therein). Variation of exponent α (a measure of peak size) against T in panel g, and α against F^ext in h. The magnitude of α (see text) correlates with the mechanical unfolding resilience and may be considered as a measure of the amount of stress stored in the non-bonding interactions. Titin, which has highest value of α, is one of the strongest proteins found in nature.