Before revision:  As f and C are changed, the stem-loop tertiary interactions rupture first  followed by unfolding of the 3^{\prime}-end hairpin (I\rightleftharpoonsF).
After revision:  As f and C are changed, the stem-loop tertiary interactions rupture first , followed by unfolding of the 3^{\prime}-end hairpin (I\rightleftharpoonsF).