Queuosine salvage proteins occur in most Eukarya as well as in a few bacteria possible via horizontal gene-transfer. Queuosine (Q) is a chemical modification found at the wobble position of tRNAs that have GUN anticodons, and it ensures faithful translation of the respective C- and U-ending codons. Most bacteria synthesize queuosine de novo, whereas eukaryotes rely solely on salvaging this essential component from the environment or the gut flora. This entry represents queuosine salvage proteins (Qng1, also known as DUF2419) which have been identified as a queuosine nucleoside glycosylases that play an essential role in allowing eukaryotic cells to salvage Q from bacterial sources and to recycle Q from endogenous tRNAs [1,2].

1: The plant, animal, and fungal micronutrient queuosine is salvaged by members of the DUF2419 protein family. Zallot R, Brochier-Amanet C, Gaston KW, Forouhar F, Limbach PA, Hunt JF, De Crecy-Lagard V; ACS Chem Biol. 2014; [Epub ahead of print] PMID:24911101

2: Queuosine salvage in fission yeast by Qng1-mediated hydrolysis to queuine. Patel BI, Heiss M, Samel-Pommerencke A, Carell T, Ehrenhofer-Murray AE; Biochem Biophys Res Commun. 2022;624:146-150. PMID:35940128