| Full name: | tRNA pseudouridine synthase B |
|---|---|
| Synonym: | TruB |
| UniProt: | D4GTP8 |
| Complex: | H/ACA RNP |
| Enzyme type: | |
| Position of modification - modification: |
:1940(None) - Y :1942(None) - Y :2605(None) - Y :2591(None) - Y |
| Level of experimental evidence: | 3 |
| Level of experimental reliability: | 2 |
nan
Cbf5 is a pseudouridine synthase of the TruB family and serves as the catalytic core of box H/ACA RNPs, which introduce site-specific Ψ residues into rRNA and snRNA in both eukaryotes and archaea. These RNPs also include the proteins Nop10, L7Ae (or Nhp2 in eukaryotes), and Gar1. Contrary to eukaryotes, the Cbf5 is not essential in H. volcanii. Deletion of Cbf5 leads to a complete loss of Ψ at specific positions (1940, 1942, 2605, 2591) in 23S rRNA (corresponding to E. coli positions 1915, 1917, 2572, 2586). Although archaeal Cbf5 has tRNA Ψ55 synthase activity in vitro, this activity was not confirmed in vivo in H. volcanii. Modifications Ψ1940 and Ψ1942 require an unpaired “UVUN” sequence (where V = A, C, or G) in the target RNA and the presence of an ACA box in the guide RNA. The formation of Ψ1942 depends on the presence of U1940 (or Ψ1940), while Ψ1940 is not formed when Ψ1942 is already present. This suggests that the two modifications occur sequentially, with Ψ1940 likely being introduced first.
| Reaction | Substrate | SubstrateType | Position | (Anti)Codon | Modified (Anti)Codon | Amino Acid Change | Transcript Name | Transcript Region | Cellular Localization | References |
|---|---|---|---|---|---|---|---|---|---|---|
| U:Y | rRNA (r) | rRNA/rRNA/prokaryotic cytosol | 1940 | |||||||
| U:Y | rRNA (r) | rRNA/rRNA/prokaryotic cytosol | 1942 | |||||||
| U:Y | rRNA (r) | rRNA/rRNA/prokaryotic cytosol | 2605 | |||||||
| U:Y | rRNA (r) | rRNA/rRNA/prokaryotic cytosol | 2591 |
| Title | Authors | Journal | Details | ||
|---|---|---|---|---|---|
| Pseudouridine formation in archaeal RNAs: The case of Haloferax volcanii. | Blaby IK, Majumder M, Chatterjee K, Jana S, Grosjean H, de Crecy-Lagard V, Gupta R | RNA | [details] | 21628430 | - |
| The presence of the ACA box in archaeal H/ACA guide RNAs promotes atypical pseudouridylation. | Majumder M; Mukhopadhyay S; Kharel P; Gupta R | RNA | [details] | 31919243 | 10.1261/rna.073734.119 |