Relating contact order to the rate of cooperative collapse in the sequential collapse model for protein folding pathways

In this Letter the kinetics of the cooperative collapse phase of the protein folding pathway within the sequential collapse model (SCM) is studied. The SCM predicts an approximate linear dependence between the logarithm of the rate of collapse and the contact order of the native topology of the collapsing region. This result is in general agreement with previous theoretical and experimental results for the collapse of small proteins, suggesting a similarity between the kinetics of the cooperative collapse phase of the SCM multi-state folding pathway of proteins of ∼100-150 amino acids, and the observed two-state folding transitions in small proteins.