EC Number   |
Natural Substrates |
|---|
  2.8.1.13 | a [protein]-S-sulfanyl-L-cysteine + uridine34 in tRNA + ATP + reduced acceptor |
the enzyme functions on tRNALys(mnm5s2UUU), tRNAGlu(mnm5s2UUC), and tRNAGln((c)mnm5s2UUG) |
| 2.8.1.13 | more |
thionucleosides are uniquely present in tRNA. In many organisms, tRNAs specific for Lys, Glu, and Gln contain hypermodified 2-thiouridine (s2U) derivatives at wobble position 34. The s2 group of s2U34 stabilizes anticodon structure, confers ribosome binding ability to tRNA and improves reading frame maintenance |
| 2.8.1.13 | more |
in the IscSeMnmA pathway, protein MnmA, together with the cysteine desulfurase IscS and sulfur transfer mediators TusA-E, performs thiolation at position 2 of U34, which occurs only in tRNALys mnm5s2UUU, tRNAGlu mnm5s2UUC, tRNAGln cmnm5s2UUG |
| 2.8.1.13 | TusE-SSH + adenylated-tRNA-uridine |
MnmA catalyzes a sulfuration reaction to synthesize 2-thiouridine at the wobble positions of tRNAGlu, tRNAGln and tRNALys in Escherichia coli |
| 2.8.1.13 | TusE-SSH + adenylated-tRNA-uridine |
the biogenesis of 2-thiouridine in Escherichia coli utilizes persulfide chemistry and proceeds through a complex sulfur-relay system by multiple sulfur mediators that select and facilitate specific sulfur flow to 2-thiouridine from various cellular sulfur pathways. TusE interacts with MnmA, a thiouridylase responsible for 2-thiouridine formation, and transfers the persulfide to it. MnmA activates the C2-position of the uracil base at the wobble position of the tRNA by forming an acyl-adenylated intermediate. Then, nucleophilic attack by the persulfide sulfur on the activated carbon generates a thiocarbonyl group by releasing the AMP |
| 2.8.1.13 | TusE-SSH + adenylated-tRNA-uridine |
the wobble bases of bacterial tRNAs responsible for NNR codons are modified to 5-methylaminomethyl-2-thiouridine (mnm5s2U). 2-thio modification of mnm5s2U is required for accurate decoding and essential for normal cell growth. IscS and MnmA are the minimum essential factors for 2-thiolation of mnm5s2U in vitro. TusE directly interacts with MnmA-tRNA to form a ternary complex. TusE appears to interact with MnmA, but not with tRNA, because TusE-tRNA interactions are not observed |
