Electron transfer component of toluate 1,2-dioxygenase system. H(+) + NAD(+) + 2 reduced [2Fe-2S]-[ferredoxin] = NADH + 2 oxidized [2Fe-2S]-[ferredoxin] Binds 1 [2Fe-2S] cluster per subunit. This dioxygenase system consists of three proteins: the two subunits of the hydroxylase component (XylX and XylY), and an electron transfer component (XylZ). Belongs to the bacterial ring-hydroxylating dioxygenase ferredoxin reductase family.