Homologous Superfamily

S-adenosylmethionine:tRNA ribosyltransferase-isomerase, QueA superfamily (IPR036100)

Short name: QueA_sf

Overlapping entries


This entry represents the S-adenosylmethionine:tRNA ribosyltransferase-isomerase, QueA. Queuosine is a hypermodified nucleoside that usually occurs in the first position of the anticodon of tRNAs specifying the amino acids asparagine, aspartate, histidine, and tyrosine. The hypermodified nucleoside is found in bacteria and eukaryotes [PMID: 8347586]. Queuosine is synthesized de novo exclusively in bacteria; for eukaryotes the compound is a nutrient factor. Queuosine biosynthesis protein, or S-adenosylmethionine:tRNA-ribosyltransferase-isomerase (QueA) catalyses the formation of the 2,3-epoxy-4,5-dihydroxycyclopentane ring of the Q precursor epoxyqueuosine (oQ). S-adenosyl-L-methionine (AdoMet) reacts with 7-aminomethyl-7-deazaguanine of tRNA at position 34 to yield adenine, methionine, and a modified tRNA with oQ at position 34.

QueA consists of two domains: domain 1 has three layers (alpha/beta/alpha), while domain 2 is a closed beta-barrel with Greek-key topology [PMID: 15822125].

GO terms

Biological Process

GO:0008616 queuosine biosynthetic process

Molecular Function

GO:0016853 isomerase activity
GO:0016740 transferase activity

Cellular Component

No terms assigned in this category.

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.