a plastoquinone + (n+1) H(+)(in) + NADH = a plastoquinol + n H(+)(out) + NAD(+) a plastoquinone + (n+1) H(+)(in) + NADPH = a plastoquinol + n H(+)(out) + NADP(+) The initiator methionine is created by RNA editing. Belongs to the complex I subunit 4 family.