a nonsignificant trendP = 0.0772
At pH 7.4, E1784K, E1784R, and E1784Q are shifted toward significantly more hyperpolarized membrane potentials compared with E1784E (P ≤ 0.0289 in all cases), whereas E1784V shows a nonsignificant trend (P = 0.0772; Fig. 2 A , inset).