Five pseudo (Y)-uridine synthases are conserved across all three life domains, including eukarya,
bacteria, and archaea. In E.coli, these are named RluA, RsuA, TruA, TruB, and TruD. These families
share poor sequence similarity. Nonetheless, these families share a core with a common fold and a conserved
This fold consists of an eight-stranded mixed beta-sheet with several helices and loops flanking the catalytic
a cleft that bisects the sheet.
Each of these families carries an essential aspartate residue that is catalytically active. This is the only residue
that is absolutely conserved in all the Y-synthases.
Depending on the enzyme, each core is additionally decorated with several secondary structural elements (
Hamma et al. 2006).
TruC is responsible for synthesis of pseudouridine from uracil-65 in E.coli tRNAs (
Del Campo et al. 2001). The catalytically conserved aspartate
is in position 54 (Asp54) .