3nmu
From Proteopedia
Crystal Structure of substrate-bound halfmer box C/D RNP
Structural highlights
Function[FLPA_PYRFU] Involved in pre-rRNA and tRNA processing. Utilizes the methyl donor S-adenosyl-L-methionine to catalyze the site-specific 2'-hydroxyl methylation of ribose moieties in rRNA and tRNA. Site specificity is provided by a guide RNA that base pairs with the substrate. Methylation occurs at a characteristic distance from the sequence involved in base pairing with the guide RNA (By similarity).[HAMAP-Rule:MF_00351] [RL7A_PYRFU] Multifunctional RNA-binding protein that recognizes the K-turn motif in ribosomal RNA, box H/ACA, box C/D and box C'/D' sRNAs (By similarity). Publication Abstract from PubMedBox C/D small nucleolar and Cajal body ribonucleoprotein particles (sno/scaRNPs) direct site-specific 2'-O-methylation of ribosomal and spliceosomal RNAs and are critical for gene expression. Here we report crystal structures of an archaeal box C/D RNP containing three core proteins (fibrillarin, Nop56/58, and L7Ae) and a half-mer box C/D guide RNA paired with a substrate RNA. The structure reveals a guide-substrate RNA duplex orientation imposed by a composite protein surface and the conserved GAEK motif of Nop56/58. Molecular modeling supports a dual C/D RNP structure that closely mimics that recently visualized by electron microscopy. The substrate-bound dual RNP model predicts an asymmetric protein distribution between the RNP that binds and methylates the substrate RNA. The predicted asymmetric nature of the holoenzyme is consistent with previous biochemical data on RNP assembly and provides a simple solution for accommodating base-pairing between the C/D guide RNA and large ribosomal and spliceosomal substrate RNAs. Structural basis for substrate placement by an archaeal box C/D ribonucleoprotein particle.,Xue S, Wang R, Yang F, Terns RM, Terns MP, Zhang X, Maxwell ES, Li H Mol Cell. 2010 Sep 24;39(6):939-49. PMID:20864039[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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