Modomics - A Database of RNA Modifications

Full name: tRNA dimethylallyltransferase, mitochondrial
Synonym: IPTase, IPPT
GI: 2507067
Orf: YOR274W
COG: COG0324
UniProt: P07884
Structures: | 3EPH | 3EPK | 3EPJ | 3EPL |
Enzyme type: dimethylallyltransferase
Position of modification - modification: t:37 - i6A


Mod5 catalyzes the transfer the delta2-isopropyl group from dimethylallyl diphosphate - a mevalonic acid derivative – to the exocyclic N6 of A36A37-containing tRNA (i6A37 formation). A single C2H2 Zn-finger-like motif present in this protein isabsent in the bacterial homolog. From a single gene MOD5, two mod5 isozymes (I, and II) are generated at the translation level (alternative translation initiation). Mod5-I is mainly located in mitochondria as well as in the cytoplasm, while Mod5-II is mainly located in the cytoplasm and in the nucleus, never in mitochondria. Sequence responsible for the subcellular distribution of the isozymes appears to reside in ‘accessory’ motifs missing from the prokaryotic counterpart (MiaA). Eukaryotic Mod5 is the ortholog of bacterial MiaA. There are no MiaA/Mod5 homologs in Archaea.

Protein sequence:


Enzymatic activities:

Reaction Substrate Type Position
A:i6A tRNA (t) Cys/GCA/prokaryotic cytosol 37
A:i6A tRNA (t) Ser/CGA/prokaryotic cytosol 37
A:i6A tRNA (t) Ser/UGA/prokaryotic cytosol 37
A:i6A tRNA (t) Ser/IGA/prokaryotic cytosol 37
A:i6A tRNA (t) Tyr/GUA/prokaryotic cytosol 37
A:i6A tRNA (t) Gly/UCC/mitochondrion 37
A:i6A tRNA (t) Tyr/GUA/mitochondrion 37


Title Authors Journal Details PubMed Id DOI
Isolation and characterization of MOD5, a gene required for isopentenylation of cytoplasmic and mitochondrial tRNAs of Saccharomyces cerevisiae. Dihanich ME, Najarian D, Clark R, Gillman EC, Martin NC, Hopper AK Mol Cell Biol [details] 3031456 -
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 -
Saccharomyces cerevisiae Mod5p-II contains sequences antagonistic for nuclear and cytosolic locations. Tolerico LH, Benko AL, Aris JP, Stanford DR, Martin NC, Hopper AK Genetics [details] 9872948 -
Plasticity and diversity of tRNA anticodon determinants of substrate recognition by eukaryotic A37 isopentenyltransferases. Lamichhane TN, Blewett NH, Maraia RJ RNA [details] 21873461 -



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