2.8.1.B3	additional information	ThiI is responsible for the formation of the modified base 4-thiouridine found at position 8 in some prokaryotic tRNAs. This base acts as a sensitive trigger for the response mechanism to UV exposure, providing protection against its damaging effects	Bacillus anthracis	?	-	?	89	
2.8.1.B3	additional information	the enzyme also catalyzes the transfer of sulfur from thiosulfate to cyanide (EC 2.8.1.1)	Escherichia coli	?	-	?	89	
2.8.1.B3	additional information	the RLD-containing protein ThiI also acts as a sulfur carrier for generating ThiS-COSH. ThiI accepts a persulfide sulfur from IscS, then transfers the sulfur for thiocarboxylate formation to the C-terminus of ThiS which is catalyzed by ThiF	Escherichia coli	?	-	?	89	
2.8.1.B3	additional information	the enzyme is not able to enhance cysteine desulfurase NifZ activity of sulfide or alanine formation	Bacillus subtilis	?	-	?	89	
2.8.1.B3	additional information	three domains of ThiI are essential for the thiolation of tRNA: a THUMP domain that binds tRNA, an AANH domain that activates the uridine residue by adenylylation, and a rhodanese domain that transfers sulfur to the activated uridine residue. Only the rhodanese domain of the ThiI protein is required for a key thiolation reaction in the synthesis of thiamine, while the other two domains (THUMP and AANH) are dispensable	Escherichia coli	?	-	?	89	
2.8.1.B3	additional information	the enzyme also displays an ATP diphosphatase activity for the adenylation of uridine	Escherichia coli	?	-	?	89	
2.8.1.B3	additional information	the enzyme is not able to enhance cysteine desulfurase NifZ activity of sulfide or alanine formation	Bacillus subtilis PS832	?	-	?	89	
2.8.1.B3	sulfide + adenylated-tRNA-uridine(position8)	sulfide is able to replace IscS/cysteine as a substrate for 4-thiouridine synthesis	Escherichia coli	tRNA-4-thiouridine(position8) + ?	-	?	401982	
2.8.1.B3	sulfurtransferase IscS-SSH + adenylated-tRNA-uridine(position8)	-	Bacillus subtilis	sulfurtransferase IscS-SH + tRNA-4-thiouridine(position8) + AMP	-	?	399029	
2.8.1.B3	sulfurtransferase IscS-SSH + adenylated-tRNA-uridine(position8)	-	Escherichia coli	sulfurtransferase IscS-SH + tRNA-4-thiouridine(position8) + AMP	-	?	399029	
2.8.1.B3	sulfurtransferase IscS-SSH + adenylated-tRNA-uridine(position8)	-	Escherichia coli	sulfurtransferase IscS-SH + tRNA-4-thiouridine(position8) + AMP	-	ir	399029	
2.8.1.B3	sulfurtransferase IscS-SSH + adenylated-tRNA-uridine(position8)	-	Thermotoga maritima	sulfurtransferase IscS-SH + tRNA-4-thiouridine(position8) + AMP	-	?	399029	
2.8.1.B3	sulfurtransferase IscS-SSH + adenylated-tRNA-uridine(position8)	the biosynthesis of 4-thiouridine in Escherichia coli tRNA requires the action of both the thiamine pathway enzyme ThiI and the cysteine desulfurase IscS. IscS catalyzes sulfur transfer from L-cysteine to ThiI, which utilizes MgATP2- to activate uridine 8 in tRNA and transfers sulfur to give s4U	Escherichia coli	sulfurtransferase IscS-SH + tRNA-4-thiouridine(position8) + AMP	-	?	399029	
2.8.1.B3	sulfurtransferase IscS-SSH + adenylated-tRNA-uridine(position8)	ThiI is a recipient of S(0) from IscS and catalyzes the ultimate sulfur transfer step in the biosynthesis of 4-thiouridine	Escherichia coli	sulfurtransferase IscS-SH + tRNA-4-thiouridine(position8) + AMP	-	?	399029	
2.8.1.B3	sulfurtransferase IscS-SSH + adenylated-tRNA-uridine(position8)	Cys456 bears a persulfide group upon incubation with sulfurtransferase IscS and cysteine, no intermediate sulfur carrier protein is chemically required	Escherichia coli	sulfurtransferase IscS-SH + tRNA-4-thiouridine(position8) + AMP	-	?	399029	
2.8.1.B3	sulfurtransferase IscS-SSH + adenylated-tRNA-uridine(position8)	sulfane sulfur generated by IscS is transferred sequentially to ThiI and then to tRNA during the in vitro synthesis of 4-thiouridine	Escherichia coli	sulfurtransferase IscS-SH + tRNA-4-thiouridine(position8) + AMP	-	?	399029	
2.8.1.B3	sulfurtransferase IscS-SSH + adenylated-tRNA-uridine(position8)	the biosynthesis of 4-thiouridine in Escherichia coli tRNA requires the action of both the thiamin pathway enzyme ThiI and the cysteine desulfurase IscS. IscS catalyzes sulfur transfer from L-cysteine to ThiI, which utilizes MgATP2- to activate uridine 8 in tRNA and transfers sulfur to give s4U. Outside of the modified uridine 8, there is no primary sequence requirement for substrate recognition. However, the secondary and tertiary structure restrictions appear sufficient to explain why s4U modification is limited in the cell to tRNA	Escherichia coli	sulfurtransferase IscS-SH + tRNA-4-thiouridine(position8) + AMP	-	?	399029	
2.8.1.B3	sulfurtransferase IscS-SSH + adenylated-tRNA-uridine(position8)	ThiI receives the sulfur transferred from the persulfide group of the sulfurtransferase IscS. Formation of a disulfide bond between Cys-344 and Cys-456 of ThiI. Evidence for the persulfide–disulfide–thiol cycle at Cys-456 of ThiI	Escherichia coli	sulfurtransferase IscS-SH + tRNA-4-thiouridine(position8) + AMP	-	?	399029	
2.8.1.B3	sulfurtransferase IscS-SSH + adenylated-tRNA-uridine(position8)	two mechanisms for the sulfur transfer mediated by ThiI are proposed: A. mechanism providing for the direct nucleophilic attack on an activated uridine species by the terminal sulfur of the persulfide on Cys-456 of ThiI. B. mechanism in which ThiI functions to generate hydrogen sulfide, which subsequently serves as the nucleophile to displace the activated oxygen of uridine 8	Escherichia coli	sulfurtransferase IscS-SH + tRNA-4-thiouridine(position8) + AMP	-	?	399029	
2.8.1.B3	sulfurtransferase IscS-SSH + adenylated-tRNA-uridine(position8)	-	Bacillus subtilis PS832	sulfurtransferase IscS-SH + tRNA-4-thiouridine(position8) + AMP	-	?	399029	
2.8.1.B3	sulfurtransferase IscS-SSH + adenylated-tRNA-uridine(position8)	-	Thermotoga maritima ATCC 43589	sulfurtransferase IscS-SH + tRNA-4-thiouridine(position8) + AMP	-	?	399029