Full name: tRNA (5-methylaminomethyl-2-thiouridylate)-methyltransferase / FAD-dependent cmnm(5)s(2)U34 oxidoreductase
Synonym: TrmC, MnmC
GI: 20140544
Orf: yfcK, b2324
COG: COG4121
UniProt: P77182
Structures: | 3AWI | 3PS9 |
Enzyme type: methyltransferase/oxidoreductase
Position of modification - modification: t:34 - mnm5s2U
t:34 - mnm5U


In E.coli (and many other bacteria) it is a bifunctional enzyme, composed of two domains that catalyze two successive reactions at the uridine wobble position 34 in tRNA: first a deacetylation reaction of cmnm5U into nm5U, then methylation of the amine group of nm5U to form mnm5U. In other organisms they may be unlinked (separate proteins), then identified as MnmC (former MnmC1) for the deacetylase and MnmD (former MnmC2) for the methyltransferase. In certain bacteria, the catalytic domain for the deacetylation reaction is absent in their genome and only the gene coding for MnmD is present. In other bacteria, MnmC and MnmD are both present. In E. coli MnmCD the two domains act independently. For tRNALeucmnm5Um the activity of methyltransferase domain was observed only in vitro.

Protein sequence:


Enzymatic activities:

Reaction Substrate Type Position
cmnm5U:nm5U tRNA (t) Arg/{CU/prokaryotic cytosol 34
nm5U:mnm5U tRNA (t) Arg/{CU/prokaryotic cytosol 34
nm5s2U:mnm5s2U tRNA (t) Gln/$UG/prokaryotic cytosol 34
nm5se2U:mnm5se2U tRNA (t) Gln/$UG/prokaryotic cytosol 34
cmnm5U:nm5U tRNA (t) Glu/SUC/prokaryotic cytosol 34
nm5U:mnm5U tRNA (t) Glu/SUC/prokaryotic cytosol 34
cmnm5s2U:nm5s2U tRNA (t) Glu/SUC/prokaryotic cytosol 34
nm5s2U:mnm5s2U tRNA (t) Glu/SUC/prokaryotic cytosol 34
cmnm5se2U:nm5se2U tRNA (t) Glu/SUC/prokaryotic cytosol 34
nm5se2U:mnm5se2U tRNA (t) Glu/SUC/prokaryotic cytosol 34
cmnm5U:nm5U tRNA (t) Lys/SUU/prokaryotic cytosol 34
nm5U:mnm5U tRNA (t) Lys/SUU/prokaryotic cytosol 34
cmnm5s2U:nm5s2U tRNA (t) Lys/SUU/prokaryotic cytosol 34
nm5s2U:mnm5s2U tRNA (t) Lys/SUU/prokaryotic cytosol 34
cmnm5se2U:nm5se2U tRNA (t) Lys/SUU/prokaryotic cytosol 34
nm5se2U:mnm5se2U tRNA (t) Lys/SUU/prokaryotic cytosol 34
cmnm5U:nm5U tRNA (t) Gly/{CC/prokaryotic cytosol 34
nm5U:mnm5U tRNA (t) Gly/{CC/prokaryotic cytosol 34
nm5U:mnm5U tRNA (t) Leu/)AA/prokaryotic cytosol 34
nm5U:mnm5U tRNA (t) Gln/$UG/prokaryotic cytosol 34


Title Authors Journal Details PubMed Id DOI
Identification of a bifunctional enzyme MnmC involved in the biosynthesis of a hypermodified uridine in the wobble position of tRNA. Bujnicki JM, Oudjama Y, Roovers M, Owczarek S, Caillet J, Droogmans L RNA [details] 15247431 -
Sequence-structure-function analysis of the bifunctional enzyme MnmC that catalyses the last two steps in the biosynthesis of hypermodified nucleoside mnm5s2U in tRNA. Roovers M, Oudjama Y, Kaminska KH, Purta E, Caillet J, Droogmans L, Bujnicki JM Proteins [details] 18186482 -
Assay of both activities of the bifunctional tRNA-modifying enzyme MnmC reveals a kinetic basis for selective full modification of cmnm5s2U to mnm5s2U. Pearson D, Carell T Nucleic Acids Res [details] 21306992 -
Crystal structure of the bifunctional tRNA modification enzyme MnmC from Escherichia coli. Kitamura A, Sengoku T, Nishimoto M, Yokoyama S, Bessho Y Protein Sci [details] 21574198 -
Structural basis for hypermodification of the wobble uridine in tRNA by bifunctional enzyme MnmC. Kim J, Almo SC BMC Struct Biol [details] 23617613 -
The output of the tRNA modification pathways controlled by the Escherichia coli MnmEG and MnmC enzymes depends on the growth conditions and the tRNA species. Moukadiri I, Garzon MJ, Bjork GR, Armengod ME... Nucleic Acids Res [details] 24293650 -


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