EC - Archaeosine synthase

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IntEnz Enzyme Nomenclature


Accepted name:
archaeosine synthase
Other names:
MJ1022 (gene name)
glutamine:preQ0-tRNA amidinotransferase [incorrect]
Systematic name:
L-glutamine:7-cyano-7-carbaguanine aminotransferase



In Euryarchaeota the reaction is catalysed by ArcS [1,2]. In Crenarchaeota, which do not have an ArcS homologue, the reaction is catalysed either by a homologue of EC, 7-cyano-7-deazaguanine synthase that includes a glutaminase domain (cf. EC, or by a homologue of EC, preQ1 synthase [2]. The enzyme from the Euryarchaeon Methanocaldococcus jannaschii can also use arginine and ammonium as amino donors.

Links to other databases

Enzymes and pathways: NC-IUBMB , BRENDA , ExplorEnz , ENZYME@ExPASy , KEGG , MetaCyc , UniPathway
Structural data: CSA , EC2PDB
Gene Ontology: GO:0002948


  1. Phillips, G., Chikwana, V. M., Maxwell, A., El-Yacoubi, B., Swairjo, M. A., Iwata-Reuyl, D., de Crecy-Lagard, V.
    Discovery and characterization of an amidinotransferase involved in the modification of archaeal tRNA.
    J. Biol. Chem. 285: 12706-12713 (2010). [PMID: 20129918]
  2. Phillips, G., Swairjo, M. A., Gaston, K. W., Bailly, M., Limbach, P. A., Iwata-Reuyl, D., de Crecy-Lagard, V.
    Diversity of archaeosine synthesis in crenarchaeota.
    ACS Chem. Biol. 7: 300-305 (2012). [PMID: 22032275]

[EC created 2012]