Figure 4. Changes in the lengths of cleavage site with applying force.

(a), The lengths of the cleave site (summation from the 5^th height to 16^th height) with and without force. (b), The time history of the increase of the length for heterotrimer and homotrimer. (c), The strain of each unit height at the vicinity of cleavage site. This figure shows that force induces both entropic and energetic strain to the heterotrimer but only induces energetic strain to the homotrimer. In the heterotrimer, the applied force reduces the entropy of the unfolded region and stabilizes the cleavage site by refolding it into the triple helical structure. In contrast, the force only induces uniform strain in the homotrimer.