+Search query
-Structure paper
Title | Alternative Mode of E-Site tRNA Binding in the Presence of a Downstream mRNA Stem Loop at the Entrance Channel. |
---|---|
Journal, issue, pages | Structure, Vol. 26, Issue 3, Page 437-445.e3, Year 2018 |
Publish date | Mar 6, 2018 |
Authors | Yan Zhang / Samuel Hong / Ajchareeya Ruangprasert / Georgios Skiniotis / Christine M Dunham / |
PubMed Abstract | Structured mRNAs positioned downstream of the ribosomal decoding center alter gene expression by slowing protein synthesis. Here, we solved the cryo-EM structure of the bacterial ribosome bound to an ...Structured mRNAs positioned downstream of the ribosomal decoding center alter gene expression by slowing protein synthesis. Here, we solved the cryo-EM structure of the bacterial ribosome bound to an mRNA containing a 3' stem loop that regulates translation. Unexpectedly, the E-site tRNA adopts two distinct orientations. In the first structure, normal interactions with the 50S and 30S E site are observed. However, in the second structure, although the E-site tRNA makes normal interactions with the 50S E site, its anticodon stem loop moves ∼54 Å away from the 30S E site to interact with the 30S head domain and 50S uL5. This position of the E-site tRNA causes the uL1 stalk to adopt a more open conformation that likely represents an intermediate state during E-site tRNA dissociation. These results suggest that structured mRNAs at the entrance channel restrict 30S subunit movement required during translation to slow E-site tRNA dissociation. |
External links | Structure / PubMed:29456023 / PubMed Central |
Methods | EM (single particle) |
Resolution | 3.2 - 3.5 Å |
Structure data | |
Chemicals | ChemComp-ZN: ChemComp-SF4: |
Source |
|
Keywords | RIBOSOME / 70S ribosome / dnaX / stem-loop / structured mRNA / -1 programmed frameshifting / E site |