Cooperative melting in double-stranded peptide chains through local mechanical interactions

Under an external field a double-stranded peptide chain can separate in a fragile or ductile transition. It is usually believed that these two regimes are driven either by chemical and thermal fields, or through non-local mechanical interactions. Here, we show explicitly that local mechanical interactions regulates the stability and reversibility of the cooperative/non-cooperative melting transition, which is described by a single parameter depending on an internal length scale. Our theory is applicable to a wide range of biological examples such as DNA, protein secondary structures, and the microtubules and tau proteins, for which we are able to predict the critical melting force as a function of the chain length.