v5.1.0.3
Glycine data from LIS
Type | Family |
Description | Pseudouridine synthases catalyse the isomerisation of uridine to pseudouridine (Psi) in a variety of RNA molecules, and may function as RNA chaperones. Pseudouridine is the most abundant modified nucleotide found in all cellular RNAs. There are four distinct families of pseudouridine synthases that share no global sequence similarity, but which do share the same fold of their catalytic domain(s) and uracil-binding site and are descended from a common molecular ancestor. The catalytic domain consists of two subdomains, each of which has an α+β structure that has some similarity to the ferredoxin-like fold (note: some pseudouridine synthases contain additional domains). The active site is the most conserved structural region of the superfamily and is located between the two homologous domains. These families are [ , ]:Pseudouridine synthase I, TruA.Pseudouridine synthase II, TruB, which contains and additional C-terminal PUA domain.Pseudouridine synthase RsuA. RluB, RluE and RluF are also part of this family.Pseudouridine synthase RluA. TruC, RluC and RluD belong to this family.Pseudouridine synthase TruD, which has a natural circular permutation in the catalytic domain, as well as an insertion of a family-specific α+β subdomain.This entry represents pseudouridine synthase I (TruA) from prokaryotes and tRNA pseudouridine synthase 1 (Pus1) from eukaryotes, which belongs to the TruA family. TruA from Escherichia coli modifies positions uracil-38, U-39 and/or U-40 in tRNA [ , ]. TruA contains one atom of zinc essential for its native conformation and tRNA recognition and has a strictly conserved aspartic acid that is likely to be involved in catalysis []. This protein adopts a dimeric assembly and shows two positively charged, RNA-binding clefts along their surface. Each cleft contains a highly conserved aspartic acid located at its centre. The structural domains have a topological similarity to those of other RNA-binding proteins, though the mode of interaction with tRNA appears to be unique. Pus1 from Saccharomyces cerevisiae acts at positions 27 and 28 of tRNAs, at positions 34 and 36 of intron-containing precursor tRNA(Ile), at position 35 in the intron-containing tRNA(Tyr) and at position 44 in U2 snRNA [, , ]. This enzyme also catalyses pseudouridylation of mRNAs []. |
Short Name | PsdUridine_synth_TruA |