Protein Summary

MnmA from Escherichia coli

Full name: tRNA 2-thiouridine(34) synthase
Synonym: TrmU, AsuE, YcfB
GI: 8039808
Orf: b1123
COG: COG0482
UniProt: P25745
Structures: | 2DET | 2DEU | 2DER |
Enzyme type: thiolase
Position of modification - modification: t:34 - s2U
t:34 - mnm5s2U


The biogenesis of 2-thiouridine derivatives at the wobble position 34 of bacterial tRNA requires a sulfur-relay system that involves multiple sulfur mediators. Cysteine is the donor of sulphur group. The type of proteins that compose this relay systems depends on the organism or cell considered. As far as E. coli MnmA is concerned, at least 6 proteins compose this complex relay system (IscS, TusA, TusB, TusC, TusD and TusE). U34 thiolation appears not to depend on prior posttransciptional modification of C5 atom of the uridine ring and thus can occur any time during the biogenesis of X5s2U34. A crystal structure of the MnmA-tRNA complex has been solved at 3.1 angstroms of resolution.

Protein sequence:


Enzymatic activities

Reaction Substrate Type Position
U:s2U tRNA (t) Glu/SUC/prokaryotic cytosol 34
cmnm5U:cmnm5s2U tRNA (t) Gln/UUG/prokaryotic cytosol 34
mnm5U:mnm5s2U tRNA (t) Gln/UUG/prokaryotic cytosol 34
mnm5U:mnm5s2U tRNA (t) Lys/SUU/prokaryotic cytosol 34
mnm5U:mnm5s2U tRNA (t) Glu/SUC/prokaryotic cytosol 34


Title Authors Journal Details PubMed Id DOI
MnmA and IscS are required for in vitro 2-thiouridine biosynthesis in Escherichia coli. Kambampati R, Lauhon CT Biochemistry [details] 12549933 -
Snapshots of tRNA sulphuration via an adenylated intermediate. Numata T, Ikeuchi Y, Fukai S, Suzuki T, Nureki O Nature [details] 16871210 -
Mechanistic insights into sulfur relay by multiple sulfur mediators involved in thiouridine biosynthesis at tRNA wobble positions. Ikeuchi Y, Shigi N, Kato J, Nishimura A, Suzuki T Mol Cell [details] 16387657 -
Enzymology of tRNA modification in the bacterial MnmEG pathway. Armengod ME, Moukadiri I, Prado S, Ruiz-Partida R, Benitez-Paez A, Villarroya M, Lomas R, Garzon MJ, Martinez-Zamora A, Meseguer S, Navarro-Gonzalez C Biochimie [details] 22386868 -



Last modification of this entry: 2012-11-30 14:20:54.713191
Edited by a user: magda
Edited content: Changed additional_information and comments.