6d90 | pdb_00006d90
Mammalian 80S ribosome with a double translocated CrPV-IRES, P-site tRNA and eRF1.
Structural highlights
Function[ERF1_HUMAN] Directs the termination of nascent peptide synthesis (translation) in response to the termination codons UAA, UAG and UGA. Component of the transient SURF complex which recruits UPF1 to stalled ribosomes in the context of nonsense-mediated decay (NMD) of mRNAs containing premature stop codons.[1] [U3KPD5_RABIT] Binds to the 23S rRNA.[RuleBase:RU000576] [G1SS70_RABIT] May play a role during erythropoiesis through regulation of transcription factor DDIT3.[HAMAP-Rule:MF_03122] [G1TWL4_RABIT] 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. Also functions as a cell surface receptor for laminin. Plays a role in cell adhesion to the basement membrane and in the consequent activation of signaling transduction pathways. May play a role in cell fate determination and tissue morphogenesis. Also acts as a receptor for several other ligands, including the pathogenic prion protein, viruses, and bacteria. Acts as a PPP1R16B-dependent substrate of PPP1CA.[HAMAP-Rule:MF_03016] Publication Abstract from PubMedCo-opting the cellular machinery for protein production is a compulsory requirement for viruses. The Cricket Paralysis Virus employs an Internal Ribosomal Entry Site (CrPV-IRES) to express its structural genes in the late stage of infection. Ribosome hijacking is achieved by a sophisticated use of molecular mimicry to tRNA and mRNA, employed to manipulate intrinsically dynamic components of the ribosome. Binding and translocation through the ribosome is required for this IRES to initiate translation. We report two structures, solved by single particle electron cryo-microscopy (cryoEM), of a double translocated CrPV-IRES with aminoacyl-tRNA in the peptidyl site (P site) of the ribosome. CrPV-IRES adopts a previously unseen conformation, mimicking the acceptor stem of a canonical E site tRNA. The structures suggest a mechanism for the positioning of the first aminoacyl-tRNA shared with the distantly related Hepatitis C Virus IRES. Dual tRNA mimicry in the Cricket Paralysis Virus IRES uncovers an unexpected similarity with the Hepatitis C Virus IRES.,Pisareva VP, Pisarev AV, Fernandez IS Elife. 2018 Jun 1;7. pii: 34062. doi: 10.7554/eLife.34062. PMID:29856316[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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