Hydrophobic repulsion between I71 and L89 in KY(V89L) contribute to large fluctuations at chain A flap tip. Radial distribution functions are shown for selected Cɑ atom pairs, including those of (A) residues I71 and 89, (B) residues I71′ and 89′, and (C) residues I50′ and I84. In (C), a slight flap opening is evident in all KY variants relative to the NL4–3 wild-type. (D) Jensen-Shannon divergence between KY and KY(V89L). For ease of visualization, only dihedral angles with a JSD above 0.01 are plotted. (E) Jensen-Shannon divergence between KY and KY(M90L). (F) Jensen-Shannon divergence between KY and KY(DM). PyMOL89 was used for visualization. Tube thickness and warmer colors indicate larger perturbation of dihedral angles. Residues in white had no significant difference between the two variants.