Priyanka D Abeyrathne / Cha San Koh / Timothy Grant / Nikolaus Grigorieff / Andrei A Korostelev /
PubMed 要旨
Internal ribosome entry sites (IRESs) mediate cap-independent translation of viral mRNAs. Using electron cryo-microscopy of a single specimen, we present five ribosome structures formed with the ...Internal ribosome entry sites (IRESs) mediate cap-independent translation of viral mRNAs. Using electron cryo-microscopy of a single specimen, we present five ribosome structures formed with the Taura syndrome virus IRES and translocase eEF2•GTP bound with sordarin. The structures suggest a trajectory of IRES translocation, required for translation initiation, and provide an unprecedented view of eEF2 dynamics. The IRES rearranges from extended to bent to extended conformations. This inchworm-like movement is coupled with ribosomal inter-subunit rotation and 40S head swivel. eEF2, attached to the 60S subunit, slides along the rotating 40S subunit to enter the A site. Its diphthamide-bearing tip at domain IV separates the tRNA-mRNA-like pseudoknot I (PKI) of the IRES from the decoding center. This unlocks 40S domains, facilitating head swivel and biasing IRES translocation via hitherto-elusive intermediates with PKI captured between the A and P sites. The structures suggest missing links in our understanding of tRNA translocation.
EMDB-6643: Ensemble cryo-EM uncovers inchworm-like translocation of a viral IRES through the ribosome PDB-5juo: Saccharomyces cerevisiae 80S ribosome bound with elongation factor eEF2-GDP-sordarin and Taura Syndrome Virus IRES, Structure I (fully rotated 40S subunit) 手法: EM (単粒子) / 解像度: 4.0 Å
EMDB-6644: Ensemble cryo-EM uncovers inchworm-like translocation of a viral IRES through the ribosome PDB-5jup: Saccharomyces cerevisiae 80S ribosome bound with elongation factor eEF2-GDP-sordarin and Taura Syndrome Virus IRES, Structure II (mid-rotated 40S subunit) 手法: EM (単粒子) / 解像度: 3.3 Å
EMDB-6645: Ensemble cryo-EM uncovers inchworm-like translocation of a viral IRES through the ribosome PDB-5jus: Saccharomyces cerevisiae 80S ribosome bound with elongation factor eEF2-GDP-sordarin and Taura Syndrome Virus IRES, Structure III (mid-rotated 40S subunit) 手法: EM (単粒子) / 解像度: 4.2 Å
EMDB-6646: Ensemble cryo-EM uncovers inchworm-like translocation of a viral IRES through the ribosome PDB-5jut: Saccharomyces cerevisiae 80S ribosome bound with elongation factor eEF2-GDP-sordarin and Taura Syndrome Virus IRES, Structure IV (almost non-rotated 40S subunit) 手法: EM (単粒子) / 解像度: 4.0 Å
EMDB-6647: Ensemble cryo-EM uncovers inchworm-like translocation of a viral IRES through the ribosome PDB-5juu: Saccharomyces cerevisiae 80S ribosome bound with elongation factor eEF2-GDP-sordarin and Taura Syndrome Virus IRES, Structure V (least rotated 40S subunit) 手法: EM (単粒子) / 解像度: 4.0 Å
EMDB-6648: Ensemble cryo-EM uncovers inchworm-like translocation of a viral IRES through the ribosome PDB-5juo: Saccharomyces cerevisiae 80S ribosome bound with elongation factor eEF2-GDP-sordarin and Taura Syndrome Virus IRES, Structure I (fully rotated 40S subunit) 手法: EM (単粒子) / 解像度: 4.0 Å
EMDB-6649: Ensemble cryo-EM uncovers inchworm-like translocation of a viral IRES through the ribosome PDB-5jup: Saccharomyces cerevisiae 80S ribosome bound with elongation factor eEF2-GDP-sordarin and Taura Syndrome Virus IRES, Structure II (mid-rotated 40S subunit) 手法: EM (単粒子) / 解像度: 3.6 Å
EMDB-6650: Ensemble cryo-EM uncovers inchworm-like translocation of a viral IRES through the ribosome PDB-5jus: Saccharomyces cerevisiae 80S ribosome bound with elongation factor eEF2-GDP-sordarin and Taura Syndrome Virus IRES, Structure III (mid-rotated 40S subunit) 手法: EM (単粒子) / 解像度: 4.0 Å
EMDB-6651: Ensemble cryo-EM uncovers inchworm-like translocation of a viral IRES through the ribosome 手法: EM (単粒子) / 解像度: 4.2 Å
EMDB-6652: Ensemble cryo-EM uncovers inchworm-like translocation of a viral IRES through the ribosome PDB-5jut: Saccharomyces cerevisiae 80S ribosome bound with elongation factor eEF2-GDP-sordarin and Taura Syndrome Virus IRES, Structure IV (almost non-rotated 40S subunit) 手法: EM (単粒子) / 解像度: 3.9 Å
EMDB-6653: Ensemble cryo-EM uncovers inchworm-like translocation of a viral IRES through the ribosome PDB-5juu: Saccharomyces cerevisiae 80S ribosome bound with elongation factor eEF2-GDP-sordarin and Taura Syndrome Virus IRES, Structure V (least rotated 40S subunit) 手法: EM (単粒子) / 解像度: 3.8 Å
化合物
ChemComp-GDP: GUANOSINE-5'-DIPHOSPHATE / GDP / GDP, エネルギー貯蔵分子*YM / グアノシン二リン酸