Metal bridges can form between the S4–S5 linker and C-linker in both open and closed states. Representative current traces of selected C-linker mutants with V361C and A364C. Currents were elicited by voltage steps to −120 mV from a holding potential of 0 mV, followed by a voltage step to +50 mV. Currents were recorded in the absence (black) or presence (red) of 1 µM Cd²⁺ from excised inside-out patches expressing the various mutants as indicated. For the V361CQ476C and A364CS473C mutants, currents recorded in response to a 1-s hyperpolarizing pulse from 0 to −120 mV are also shown to highlight the slowing of activation by Cd²⁺. For the A364CS474C, A364CQ476C, and A364CR478C mutants, currents recorded in response to a 2-s hyperpolarizing pulse from 0 to −120 mV are also shown to highlight the slowing of activation by Cd²⁺.