The C terminal domain of tRNA Pseudouridine synthase II adopts a PUA (Pfam:PF01472) fold, with a four-stranded mixed beta-sheet flanked by one alpha-helix on each side. It allows for binding of the enzyme to RNA, as well as stabilisation of the RNA molecule [1].

1: Crystal structure of the apo forms of psi 55 tRNA pseudouridine synthase from Mycobacterium tuberculosis: a hinge at the base of the catalytic cleft. Chaudhuri BN, Chan S, Perry LJ, Yeates TO; J Biol Chem. 2004;279:24585-24591. PMID:15028724