RNA Pseudouridylate Synthase Domain Containing Protein 4 (RPUSD4)

RPUSD4 Belongs to the pseudouridine synthase rluA family. RluA is a dual-specificity enzyme responsible for pseudouridylating 23S rRNA and several tRNAs. The 2.05 A resolution structure of RluA bound to a substrate RNA comprising the anticodon stem loop of tRNA(Phe) reveals that enzyme binding induces a dramatic reorganization of the RNA. Sequence conservation, the cocrystal structure, and the results of structure-guided mutagenesis suggest that RluA recognizes its substrates indirectly by probing RNA loops for their ability to adopt the reorganized fold. The planar, cationic side chain of an arginine intercalates between the reverse-Hoogsteen base pair and the bottom pair of the anticodon stem, flipping the nucleotide to be modified into the active site of RluA.