Pseudouridine synthases catalyze the isomerization of specific uridines in an RNA molecule to pseudouridines (5-ribosyluracil, psi).
Pseudouridine synthases contains the RsuA/RluD, TruA, TruB and TruD families. This group consists of eukaryotic, bacterial and archeal pseudouridine synthases. Some psi sites such as psi55,13,38 and 39 in tRNA are highly conserved, being in the same position in eubacteria, archeabacteria and eukaryotes. Other psi sites occur in a more restricted fashion, for example psi2604in 23S RNA made by E.coli RluF has only been detected in E.coli. Human dyskerin with the help of guide RNAs makes the hundreds of psueudouridnes present in rRNA and small nuclear RNAs (snRNAs). Mutations in human dyskerin cause X-linked dyskeratosis congenitas. Missense mutation in human PUS1 causes mitochondrial myopathy and sideroblastic anemia (MLASA).
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