“…In the recording, proton currents were measured from a holding potential of −60 mV to a first prestep and a second test-step with rest intervals at −60 mV ( 37 , 38 ). The proton channel conductance is determined by the equation: G(V test ) = (I test -I tail )/(V test -V tail ) , where I test is the current at V test , measured at the end of the depolarization step, and I tail is the current at V tail , measured at the beginning of the repolarization step.…”