Protein Summary

MiaB from Escherichia coli

Full name: tRNA (N6-isopentenyl adenosine(37)-C2)-methylthiotransferase
Synonym: YleA
GI: 83288203
Orf: b0661
COG: COG0621
UniProt: P0AEI1
Enzyme type: methylthiotransferase
Position of modification - modification: t:37 - ms2i6A


Bacterial MiaB works on A36-i6A37-containing tRNA. It displays a N-terminal TRAM domain and a C-terminal catalytic radical SAM domain with two [4Fe-4S] clusters coordinated with 3 cysteines and an exchangeable S-AdoMet. It works with IcsS/IcsU as the donor of sulfur. Belongs to the same family of methylthiotransferases as B subtilis MTaB (YqeV), mammalian MtaB (Cdkal1) and protein methylthiotransferase RimO. A MiaB-CDKAL1-like enzyme is present in Archaea, while MiaA/Mod5 is totally absent. Its function is still elusive (2012). MnmE-GTpase negatively regulates the activity of MiaG in E. coli.

Protein sequence:


Enzymatic activities

Reaction Substrate Type Position
i6A:ms2i6A tRNA (t) Cys/GCA/prokaryotic cytosol 37
i6A:ms2i6A tRNA (t) Leu/UAA/prokaryotic cytosol 37
i6A:ms2i6A tRNA (t) Phe/GAA/prokaryotic cytosol 37
i6A:ms2i6A tRNA (t) Ser/UGA/prokaryotic cytosol 37
i6A:ms2i6A tRNA (t) Ser/CGA/prokaryotic cytosol 37
i6A:ms2i6A tRNA (t) Trp/CCA/prokaryotic cytosol 37
i6A:ms2i6A tRNA (t) Tyr/GUA/prokaryotic cytosol 37


Title Authors Journal Details PubMed Id DOI
MiaB protein is a bifunctional radical-S-adenosylmethionine enzyme involved in thiolation and methylation of tRNA. Pierrel F, Douki T, Fontecave M, Atta M J Biol Chem [details] 15339930 -
Identification of the miaB gene, involved in methylthiolation of isopentenylated A37 derivatives in the tRNA of Salmonella typhimurium and Escherichia coli. Esberg B, Leung HC, Tsui HC, Bjork GR, Winkler ME J Bacteriol [details] 10572129 -
Formation of thiolated nucleosides present in tRNA from Salmonella enterica serovar Typhimurium occurs in two principally distinct pathways. Leipuviene R, Qian Q, Bjork GR J Bacteriol [details] 14729702 -
Enzymatic modification of tRNAs: MiaB is an iron-sulfur protein. Pierrel F, Bjork GR, Fontecave M, Atta M J Biol Chem [details] 11882645 -
Evidence that the folate-dependent proteins YgfZ and MnmEG have opposing effects on growth and on activity of the iron-sulfur enzyme MiaB. Waller JC, Ellens KW, Hasnain G, Alvarez S, Rocca JR, Hanson AD J Bacteriol [details] 22081392 -
TRAM, a predicted RNA-binding domain, common to tRNA uracil methylation and adenine thiolation enzymes. Anantharaman V, Koonin EV, Aravind L FEMS Microbiol Lett [details] 11313137 -



Last modification of this entry: 2014-01-20 10:48:21.323880
Edited by a user: magda
Edited content: Changed papers.