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5tzs
From Proteopedia
Architecture of the yeast small subunit processome
Structural highlights
Function[RS7A_YEAST] Involved in nucleolar processing of pre-18S ribosomal RNA and ribosome assembly.[1] [UTP21_YEAST] Involved in nucleolar processing of pre-18S ribosomal RNA and ribosome assembly.[2] [RCL1_YEAST] Does not have cyclase activity. Plays a role in 40S-ribosomal-subunit biogenesis in the early pre-rRNA processing steps at sites A0, A1 and A2 that are required for proper maturation of the 18S RNA. Essential for viability. [NEP1_YEAST] S-adenosyl-L-methionine-dependent pseudouridine N(1)-methyltransferase that methylates pseudouridine at position 1189 (Psi1189) in 18S rRNA. Involved the biosynthesis of the hypermodified N1-methyl-N3-(3-amino-3-carboxypropyl) pseudouridine (m1acp3-Psi) conserved in eukaryotic 18S rRNA. N1-methylation is independent on acp-modification at the N3-position of U1191. Has also an essential role in 40S ribosomal subunit biogenesis independent on its methyltransferase activity, facilitating the incorporation of ribosomal protein S19 (RPS19A/RPS19B) during the formation of pre-ribosomes.[3] [4] [5] [6] [7] [RRP9_YEAST] Involved in nucleolar processing of pre-18S ribosomal RNA. Required for efficient pre-rRNA cleavage at sites A0, A1 and A2, and biosynthesis of 18S rRNA.[8] [RS9A_YEAST] Involved in nucleolar processing of pre-18S ribosomal RNA and ribosome assembly.[9] [SNU13_YEAST] Common component of the spliceosome and rRNA processing machinery. In association with the spliceosomal U4/U6.U5 tri-snRNP particle, required for splicing of pre-mRNA. In association with box C/D snoRNPs, required for processing of pre-ribosomal RNA (rRNA) and site-specific 2'-O-methylation of substrate RNAs. Essential for the accumulation and stability of U4 snRNA, U6 snRNA, and box C/D snoRNAs.[10] [11] [12] [RS6A_YEAST] Involved in nucleolar processing of pre-18S ribosomal RNA and ribosome assembly.[13] Publication Abstract from PubMedThe small subunit (SSU) processome, a large ribonucleoprotein particle, organizes the assembly of the eukaryotic small ribosomal subunit by coordinating the folding, cleavage, and modification of nascent pre-ribosomal RNA (rRNA). Here, we present the cryo-electron microscopy structure of the yeast SSU processome at 5.1-angstrom resolution. The structure reveals how large ribosome biogenesis complexes assist the 5' external transcribed spacer and U3 small nucleolar RNA in providing an intertwined RNA-protein assembly platform for the separate maturation of 18S rRNA domains. The strategic placement of a molecular motor at the center of the particle further suggests a mechanism for mediating conformational changes within this giant particle. This study provides a structural framework for a mechanistic understanding of eukaryotic ribosome assembly in the model organism Saccharomyces cerevisiae. Architecture of the yeast small subunit processome.,Chaker-Margot M, Barandun J, Hunziker M, Klinge S Science. 2017 Jan 13;355(6321). pii: eaal1880. doi: 10.1126/science.aal1880. Epub, 2016 Dec 15. PMID:27980088[14] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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