Possible origins of mutational effects of K539L, C618R, and R564L derived from the snapshots of various mutant simulations at 44 ns. The JH2 C-helix is shown in orange, the β-4 sheet in blue, and the β-5 sheet in red. In all three cases, the local conformation near V617 is distorted, although through different mechanisms. In K539L, L539 moves away from the highly-charged region of D620 and R541 and brings down E543, D544. In R564L, the strong interactions between R564 and E543/D544 are totally missing. In C618R, R618 moves toward E543/D544 and forms strong interactions with them.