Functional effects of individual mutations of conserved residues in the S4C-term. (A) Sequence alignment with some conserved S4C-term and S5N-term residues in blue. The homology model showing residues with side-chains and putative interactions (A, Lower). (B–H) ZD7288-subtracted currents and GV curves: (B) R350A, (C) F351A, (D) Q354A, (E) W355A, (F) E356A, (G) R367A. Note: these currents were not leak-subtracted with ZD7288. (H) D471A.