5mc6 | pdb_00005mc6

Cryo-EM structure of a native ribosome-Ski2-Ski3-Ski8 complex from S. cerevisiae

Loading... Status: waiting for Mol* initialization Structural highlights 5mc6 is a 87 chain structure with sequence from Baker's yeast and Saccharomyces cerevisiae (strain atcc 204508 / s288c). Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. NonStd Res: 5CT, UNK Activity: RNA helicase, with EC number 3.6.4.13 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function [RS6A_YEAST] Involved in nucleolar processing of pre-18S ribosomal RNA and ribosome assembly. [RL4A_YEAST] Participates in the regulation of the accumulation of its own mRNA. [GBLP_YEAST] Located at the head of the 40S ribosomal subunit in the vicinity of the mRNA exit channel, it serves as a scaffold protein that can recruit other proteins to the ribosome. Involved in the negative regulation of translation of a specific subset of proteins. [RL401_YEAST] Ubiquitin: exists either covalently attached to another protein, or free (unanchored). When covalently bound, it is conjugated to target proteins via an isopeptide bond either as a monomer (monoubiquitin), a polymer linked via different Lys residues of the ubiquitin (polyubiquitin chains) or a linear polymer linked via the initiator Met of the ubiquitin (linear polyubiquitin chains). Polyubiquitin chains, when attached to a target protein, have different functions depending on the Lys residue of the ubiquitin that is linked: Lys-6-linked may be involved in DNA repair; Lys-11-linked is involved in ERAD (endoplasmic reticulum-associated degradation) and in cell-cycle regulation; Lys-29-linked is involved in lysosomal degradation; Lys-33-linked is involved in kinase modification; Lys-48-linked is involved in protein degradation via the proteasome; Lys-63-linked is involved in endocytosis, and DNA-damage responses. Linear polymer chains formed via attachment by the initiator Met lead to cell signaling. Ubiquitin is usually conjugated to Lys residues of target proteins, however, in rare cases, conjugation to Cys or Ser residues has been observed. When polyubiquitin is free (unanchored-polyubiquitin), it also has distinct roles, such as in activation of protein kinases, and in signaling (By similarity). 60S ribosomal protein L40: component of the 60S subunit of the ribosome. Ribosomal protein L40 is essential for translation of a subset of cellular transcripts, including stress response transcripts, such as DDR2. [RS14A_YEAST] Involved in nucleolar processing of pre-18S ribosomal RNA and ribosome assembly. [RS19A_YEAST] Required for proper maturation of the small (40S) ribosomal subunit. Binds to 40s pre-ribosomal particles, probably required after association of NOC4 but before association of ENP1, TSR1 and RIO2 with 20/21S pre-rRNA. [RL25_YEAST] This protein binds to a specific region on the 26S rRNA. [SKI3_YEAST] Component of the SKI complex involved in 3'-mRNA degradation pathway. Represses dsRNA virus propagation by specifically blocking translation of viral mRNAs, perhaps recognizing the absence of CAP or poly(A). Essential for cell growth only in the presence of M1 replicon. [RS27A_YEAST] Ubiquitin exists either covalently attached to another protein, or free (unanchored). When covalently bound, it is conjugated to target proteins via an isopeptide bond either as a monomer (monoubiquitin), a polymer linked via different Lys residues of the ubiquitin (polyubiquitin chains) or a linear polymer linked via the initiator Met of the ubiquitin (linear polyubiquitin chains). Polyubiquitin chains, when attached to a target protein, have different functions depending on the Lys residue of the ubiquitin that is linked: Lys-6-linked may be involved in DNA repair; Lys-11-linked is involved in ERAD (endoplasmic reticulum-associated degradation) and in cell-cycle regulation; Lys-29-linked is involved in lysosomal degradation; Lys-33-linked is involved in kinase modification; Lys-48-linked is involved in protein degradation via the proteasome; Lys-63-linked is involved in endocytosis, and DNA-damage responses. Linear polymer chains formed via attachment by the initiator Met lead to cell signaling. Ubiquitin is usually conjugated to Lys residues of target proteins, however, in rare cases, conjugation to Cys or Ser residues has been observed. When polyubiquitin is free (unanchored-polyubiquitin), it also has distinct roles, such as in activation of protein kinases, and in signaling (By similarity). 40S ribosomal protein S31 is a component of the 40S subunit of the ribosome (By similarity). [IF5A1_YEAST] mRNA-binding protein involved in translation elongation. Has an important function at the level of mRNA turnover, probably acting downstream of decapping. Involved in actin dynamics and cell cycle progression, mRNA decay and probably in a pathway involved in stress response and maintenance of cell wall integrity. Essential for polarized growth, a process necessary for G1/S transition. May mediate large range of effects of the polyamine spermidine in the cell. [RS2_YEAST] Important in the assembly and function of the 40S ribosomal subunit. Mutations in this protein affects the control of translational fidelity. Involved in nucleolar processing of pre-18S ribosomal RNA and ribosome assembly. [RSSA1_YEAST] Required for the assembly and/or stability of the 40S ribosomal subunit. Required for the processing of the 20S rRNA-precursor to mature 18S rRNA in a late step of the maturation of 40S ribosomal subunits. [RS21A_YEAST] Required for the processing of the 20S rRNA-precursor to mature 18S rRNA in a late step of the maturation of 40S ribosomal subunits. Has a physiological role leading to 18S rRNA stability. [RL5_YEAST] Binds 5S RNA and is required for 60S subunit assembly. [SKI8_YEAST] Involved in double-strand break (DSB) formation during meiotic recombination through stabilization of SPO11 association with meiotic chromosome and helping SPO11 to recruit other DSB proteins like REC102 and REC104 to meiotic chromosomes. Also component of the SKI complex involved in 3'-mRNA degradation pathway. Represses dsRNA virus propagation by specifically blocking translation of viral mRNAs, perhaps recognizing the absence of CAP or poly(A). Essential for controlling the propagation of M double-stranded RNA (dsRNA) and thus for preventing virus-induced cytopathology. [RS9A_YEAST] Involved in nucleolar processing of pre-18S ribosomal RNA and ribosome assembly. [RS7A_YEAST] Involved in nucleolar processing of pre-18S ribosomal RNA and ribosome assembly. [RL37A_YEAST] Binds to the 23S rRNA (By similarity). [RS15_YEAST] Involved in the nuclear export of the small ribosomal subunit. Has a role in the late stage of the assembly of pre-40S particles within the nucleus and controls their export to the cytoplasm. [RS18A_YEAST] Located at the top of the head of the 40S subunit, it contacts several helices of the 18S rRNA (By similarity).[HAMAP-Rule:MF_01315] [RL11A_YEAST] Binds to 5S ribosomal RNA. [SKI2_YEAST] RNA helicase component of the SKI complex involved in 3'-mRNA degradation pathway. Represses dsRNA virus propagation by specifically blocking translation of viral mRNAs, perhaps recognizing the absence of CAP or poly(A). Essential for cell growth only in the presence of M1 replicon. Publication Abstract from PubMed Ski2-Ski3-Ski8 (Ski) is a helicase complex functioning with the RNA-degrading exosome to mediate the 3'-5' messenger RNA (mRNA) decay in turnover and quality-control pathways. We report that the Ski complex directly associates with 80S ribosomes presenting a short mRNA 3' overhang. We determined the structure of an endogenous ribosome-Ski complex using cryo-electron microscopy (EM) with a local resolution of the Ski complex ranging from 4 angstroms (A) in the core to about 10 A for intrinsically flexible regions. Ribosome binding displaces the autoinhibitory domain of the Ski2 helicase, positioning it in an open conformation near the ribosomal mRNA entry tunnel. We observe that the mRNA 3' overhang is threaded directly from the small ribosomal subunit to the helicase channel of Ski2, primed for ongoing exosome-mediated 3'-5' degradation. The cryo-EM structure of a ribosome-Ski2-Ski3-Ski8 helicase complex.,Schmidt C, Kowalinski E, Shanmuganathan V, Defenouillere Q, Braunger K, Heuer A, Pech M, Namane A, Berninghausen O, Fromont-Racine M, Jacquier A, Conti E, Becker T, Beckmann R Science. 2016 Dec 16;354(6318):1431-1433. PMID:27980209 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Receptor for activated protein kinase C 1

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