InterPro domain: IPR015221

Ubiquitin related modifier 1 (Urm1) is a ubiquitin related protein that modifies proteins in the yeast ubiquitin-like urmylation pathway [ 1 ]. Structural comparisons and phylogenetic analysis of the ubiquitin superfamily has indicated that Urm1 has the most conserved structural and sequence features of the common ancestor of the entire superfamily [ 2 ]. Urm1 acts as a sulfur carrier required for 2-thiolation of mcm5S2U at tRNA wobble positions of cytosolic tRNA(Lys), tRNA(Glu) and tRNA(Gln) [ 3 ].

1. Solution structure of Urm1 and its implications for the origin of protein modifiers. Proc. Natl. Acad. Sci. U.S.A. 103, 11625-30
2. Urmylation: a ubiquitin-like pathway that functions during invasive growth and budding in yeast. Mol. Biol. Cell 14, 4329-41
3. Role of the ubiquitin-like protein Urm1 as a noncanonical lysine-directed protein modifier. Proc. Natl. Acad. Sci. U.S.A. 108, 1763-70