Channels with hydrogen-bonding residues at E356 and N370 gate normally. Representative traces of the current (black) and fluorescence (red) from (A) E356N*, (B) N370E*, and (C) E356N-N370E* channels. (D) Normalized G(V) and F(V) curves of wt*, E356N*, N370E*, and E356N-N370E* channels. Mean ± SEM.