Reaction catalyzed by tRNA uracil 4-sulfurtransferase (2.8.1.4)
ATP
+
[ThiI sulfur-carrier protein]-S-sulfanyl-L-cysteine
+
uracil in tRNA
+
2
reduced ferredoxin [iron-sulfur] cluster
=
AMP
+
+
4-thiouracil in tRNA
+
[ThiI sulfur-carrier protein]-L-cysteine
+
2
oxidized ferredoxin [iron-sulfur] cluster
ATP
+
[ThiI sulfur-carrier protein]-S-sulfanyl-L-cysteine
+
uracil in tRNA
+
2 reduced ferredoxin [iron-sulfur] cluster
=
AMP
+
diphosphate
+
4-thiouracil in tRNA
+
[ThiI sulfur-carrier protein]-L-cysteine
+
2 oxidized ferredoxin [iron-sulfur] cluster
