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-Structure paper
Title | Structure of the mammalian ribosome as it decodes the selenocysteine UGA codon. |
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Journal, issue, pages | Science, Vol. 376, Issue 6599, Page 1338-1343, Year 2022 |
Publish date | Jun 17, 2022 |
Authors | Tarek Hilal / Benjamin Y Killam / Milica Grozdanović / Malgorzata Dobosz-Bartoszek / Justus Loerke / Jörg Bürger / Thorsten Mielke / Paul R Copeland / Miljan Simonović / Christian M T Spahn / |
PubMed Abstract | The elongation of eukaryotic selenoproteins relies on a poorly understood process of interpreting in-frame UGA stop codons as selenocysteine (Sec). We used cryo-electron microscopy to visualize Sec ...The elongation of eukaryotic selenoproteins relies on a poorly understood process of interpreting in-frame UGA stop codons as selenocysteine (Sec). We used cryo-electron microscopy to visualize Sec UGA recoding in mammals. A complex between the noncoding Sec-insertion sequence (SECIS), SECIS-binding protein 2 (SBP2), and 40 ribosomal subunit enables Sec-specific elongation factor eEFSec to deliver Sec. eEFSec and SBP2 do not interact directly but rather deploy their carboxyl-terminal domains to engage with the opposite ends of the SECIS. By using its Lys-rich and carboxyl-terminal segments, the ribosomal protein eS31 simultaneously interacts with Sec-specific transfer RNA (tRNA) and SBP2, which further stabilizes the assembly. eEFSec is indiscriminate toward l-serine and facilitates its misincorporation at Sec UGA codons. Our results support a fundamentally distinct mechanism of Sec UGA recoding in eukaryotes from that in bacteria. |
External links | Science / PubMed:35709277 / PubMed Central |
Methods | EM (single particle) |
Resolution | 2.8 - 3.1 Å |
Structure data | EMDB-14751, PDB-7zjw: EMDB-14752, PDB-7zjx: |
Chemicals | ChemComp-GTP: ChemComp-SER: ChemComp-MG: ChemComp-K: ChemComp-ZN: ChemComp-NA: ChemComp-HOH: |
Source |
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Keywords | RIBOSOME / Selenocysteine / recoding / 80S |