Modomics - A Database of RNA Modifications

ID Card:

Full name: (Dimethylallyl)adenosine tRNA methylthiotransferase MiaB
Synonym: YmcB, BSU17010
GI: 16078764
COG: COG0621
UniProt: O31778
Alpha Fold Predicted Structure: AF-O31778-F1
Enzyme type: methylthiotransferase predicted

Protein sequence:



Corresponds to E. coli MiaB ortholog. Posesses 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. 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).

Reaction Substrate SubstrateType Position (Anti)Codon Modified (Anti)Codon Amino Acid Change Transcript Name Transcript Region Cellular Localization References
i6A:ms2i6A tRNA (t) many/many/prokaryotic cytosol 37 20472640   

Alpha Fold Predicted Structure:

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Protein sequence:

Secondary Structure Alphabet

  • G: 3-turn helix (310helix)
  • H: α-helix
  • I: 𝝅-helix (5 - turn helix)
  • T: Hydrogen Bonded Turn
  • B: β-sheet
  • S: Bend
  • C: Coil (residues not present in any of the above conformations)
  • N: Not assigned

Download PDB Structures & DSSP Secondary Structures:

Alpha Fold Pdb Files   AF-O31778-F1.pdb  
Alpha Fold Pdbx/mmCIF Files   AF-O31778-F1.cif  
DSSP Secondary Structures   O31778.dssp  


Title Authors Journal Details PubMed Id DOI
Structural bioinformatics analysis of enzymes involved in the biosynthesis pathway of the hypermodified nucleoside ms(2)io(6)A37 in tRNA. Kaminska KH, Baraniak U, Boniecki M, Nowaczyk K, Czerwoniec A, Bujnicki JM Proteins [details] 17910062 -
Functional characterization of the YmcB and YqeV tRNA methylthiotransferases of Bacillus subtilis. Anton BP, Russell SP, Vertrees J, Kasif S, Raleigh EA, Limbach PA, Roberts RJ Nucleic Acids Res [details] 20472640 -
The methylthiolation reaction mediated by the Radical-SAM enzymes. Atta M, Arragain S, Fontecave M, Mulliez E, Hunt JF, Luff JD, Forouhar F Biochim Biophys Acta [details] 22178611 -