ID 2.6.1.97 DE archaeosine synthase. CA 7-cyano-7-carbaguanosine(15) in tRNA + H2O + L-glutamine = CA archaeosine(15) in tRNA + L-glutamate. CC -!- In Euryarchaeota the reaction is catalyzed by ArcS. CC -!- In Crenarchaeota, which do not have an ArcS homolog, the reaction is CC catalyzed either by a homolog of EC 6.3.4.20 that includes a CC glutaminase domain (cf. EC 3.5.1.2), or by a homolog of EC 1.7.1.13. CC -!- The enzyme from the Euryarchaeon Methanocaldococcus jannaschii can CC also use arginine and ammonium as amino donors. DR D4GTN6, ARCS_HALVD ; Q58428, ARCS_METJA ; //