Recombinant Queuosine-tRNA galactosyltransferase (QTGAL) fragment (residues 1-346) from Homo sapiens, designed for structural and biochemical studies. This fragment represents a stable and soluble unit of the enzyme, facilitating investigations into its role in tRNA modification and translational regulation.

Queuosine-tRNA galactosyltransferase (QTGAL), encoded by the B3GNTL1 gene, is a glycosyltransferase that catalyzes the galactosylation of cytoplasmic tRNA(Tyr) at the queuosine-modified position 34. This modification forms galactosyl-queuosine(34), which is essential for regulating protein translation by slowing elongation at cognate codons and suppressing stop codon readthrough. The enzyme is localized in the cytoplasm, underscoring its direct involvement in cytoplasmic tRNA processing and translational control mechanisms.