3hay
From Proteopedia
Crystal structure of a substrate-bound full H/ACA RNP from Pyrococcus furiosus
Structural highlights
FunctionTRUB_PYRFU Could be responsible for synthesis of pseudouridine from uracil-55 in the psi GC loop of transfer RNAs (By similarity). Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedH/ACA RNAs form ribonucleoprotein complex (RNP) with proteins Cbf5, Nop10, L7Ae, and Gar1 and guide site-specific conversion of uridine into pseudouridine in cellular RNAs. The crystal structures of H/ACA RNP with substrate bound at the active site cleft reveal that the substrate is recruited through sequence-specific pairing with guide RNA and essential protein contacts. Substrate binding leads to a reorganization of a preset pseudouridylation pocket and an adaptive movement of the PUA domain and the lower stem of the H/ACA RNA. Moreover, a thumb loop flips from the Gar1-bound state in the substrate-free RNP structure to tightly associate with the substrate. Mutagenesis and enzyme kinetics analysis suggest a critical role of Gar1 and the thumb in substrate turnover, particularly in product release. Comparison with tRNA Psi55 synthase TruB reveals the structural conservation and adaptation between an RNA-guided and stand-alone pseudouridine synthase and provides insight into the guide-independent activity of Cbf5. Structural mechanism of substrate RNA recruitment in H/ACA RNA-guided pseudouridine synthase.,Duan J, Li L, Lu J, Wang W, Ye K Mol Cell. 2009 May 14;34(4):427-39. PMID:19481523[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also
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