[protein] with 2 [4Fe-4S] clusters + sulfite + 6 AH2 + 2 S-adenosyl-L-methionine = [protein] with [8Fe-9S-C] cluster + 5'-deoxyadenosine + L-methionine + 6 A + S-adenosyl-L-homocysteine + 3 H2O + 8 H(+) — reaction