This group consists of eukaryotic pseudouridine synthases similar to Saccharomyces cerevisiae Pus1p, S. cerevisiae Pus2p, Caenorhabditis elegans Pus1p and human PUS1. Pseudouridine synthases catalyze the isomerization of specific uridines in an RNA molecule to pseudouridines (5-ribosyluracil, psi). No cofactors are required. S. cerevisiae Pus1p catalyzes the formation of psi34 and psi36 in the intron-containing tRNAIle, psi35 in the intron-containing tRNATyr, psi27 and/or psi28 in several yeast cytoplasmic tRNAs and, psi44 in U2 small nuclear RNA (U2 snRNA). The presence of the intron is required for the formation of psi 34, 35 and 36. In addition S. cerevisiae PUS1 makes are psi 26, 65 and 67. C. elegans Pus1p does not modify psi44 in U2 snRNA. Mouse Pus1p makes psi27/28 in pre- tRNASer , tRNAVal and tRNAIle, psi 34/36 in tRNAIle and, psi 32 and potentially 67 in tRNAVal. Psi44 in U2 snRNA and psi32 in tRNAs are highly phylogenetically conserved. Psi 26,27,28,34,35,36,65 and 67 in tRNAs are less highly conserved. Mouse Pus1p regulates nuclear receptor activity through pseudouridylation of Steroid Receptor RNA Activator. Missense mutation in human PUS1 causes mitochondrial myopathy and sideroblastic anemia (MLASA).
Jiyao W et al.(2023). "The conserved domain database in 2023.",