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Printable Handouts
Navigable Slide Index
- Introduction
- Ribosomes and translation
- Molecular composition of the ribosome
- Why is the ribosome so big?
- The ribosome has a big substrate
- Crystal structure of the 70S ribosome
- The mRNA channel in the 30S subunit
- tRNA positions in the A, P & E sites
- Location of the tRNA in the ribosome
- Positions of A- and P-tRNA in the ribosome
- Ribosome structural dynamics during translocation
- Positions of tRNA in the ribosome
- The hybrid states elongation cycle
- States of tRNA binding during movement
- Movement of tRNA through the ribosome
- Distortion of tRNA structure by the ribosome
- tRNA structure distortion by ribosomal P, E sites
- The ribosome is a molecular machine
- Translocational mechanics: the Ratchet model
- The rachet model
- tRNA predicted positions in cryo-EM experiment
- Inferred relationship - ratcheting, hybrid states
- Testing intersubunit movement using FRET
- The FRET experiment
- FRET experiment results
- Changes between S6-L9 and S11-L9
- Reversed donor and acceptor fluors
- Peptidyl-tRNA deacylation by puromycin reaction
- Peptidyl-tRNA deacylation causes rotation
- Reaction of a hybrid-state complex with EF-G-GTP
- Reversal of intersubunit rotation
- Intersubunit movement in single ribosomes
- Conclusions from FRET experiments
- Testing the ratchet model for translocation
- Positions of introduced cysteines in L2 and S6
- Juxtaposition of cysteines across subunit interface
- Testing the disulfide bridge formation
- Disulfide crosslinking prevents subunit dissociation
- Identification of the S6-L2 crosslink
- Crosslinking prevents polypeptide synthesis
- Crosslinked ribosomes (1)
- Crosslinked ribosomes (2)
- What about translocation?
- Translocation assay
- Intersubunit crosslinking prevents translocation (1)
- Translocation assay (toeprinting)
- Intersubunit crosslinking prevents translocation (2)
- Relative movement is required for translocation
- The strictly EF-G-dependent step of translocation
- What defines the mechanism of translocation?
- The peptidyl transferase inhibitor sparsomycin
- Catalysis of translocation by sparsomycin
- The energetics of translocation
- tRNA interactions in the 50S E-site
- E-tRNA interactions with the ribosome
- Exit of the deacylated tRNA from the E-site
- The elbow of E-site tRNA stacks on the L1 RNA
- Large-scale movement of the L1 arm of 23S rRNA
- Movement of 50S subunit in translocation
- Acknowledgements
- Center for Molecular Biology of RNA
Topics Covered
- Ribosomes and translation
- Molecular composition of the ribosome
- Why is the ribosome so big?
- The mRNA channel in the 30S subunit
- Positions of tRNA in the A-, P- and E-sites
- Structural dynamics of the ribosome during translocation
- The hybrid states elongation cycle
- tRNA binding during its movement through the ribosome
- The 70S ribosome
- Distortion of tRNA structure by the ribosome
- The ratchet model
- Cryo-EM experiment
- Inferred relationship between ratcheting and hybrid states
- FRET changes
- Intersubunit movement
- Testing the ratchet model for translocation
- Translocation assay
- What defines the mechanism of translocation
- Sparsomycin
- The energetics of translocation
- E-site tRNA
- The ribosome is a molecular machine
Talk Citation
Noller, H. (2008, May 15). Translocation: movement of tRNA and mRNA through the ribosome [Video file]. In The Biomedical & Life Sciences Collection, Henry Stewart Talks. Retrieved October 12, 2024, from https://doi.org/10.69645/DRKE5756.Export Citation (RIS)
Publication History
Financial Disclosures
- Prof. Harry Noller has not informed HSTalks of any commercial/financial relationship that it is appropriate to disclose.