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Dual DNA Rulers to Study the Mechanism of Ribosome Translocation with Single-Nucleotide Resolution
Published on: July 8, 2019
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Dynamic pathways of -1 translational frameshifting.
Jin Chen1, Alexey Petrov2, Magnus Johansson2
11] Department of Applied Physics, Stanford University, Stanford, California 94305-4090, USA [2] Department of Structural Biology, Stanford University School of Medicine, Stanford, California 94305-5126, USA.
Nature
|June 12, 2014
Summary
Programmed -1 ribosomal frameshifting occurs when ribosomes pause and undergo conformational changes on specific mRNA sequences, enabling translation of new amino acid sequences.
Area of Science:
- Molecular Biology
- Genetics
- Biochemistry
Background:
- Ribosomal frameshifting is a rare but programmed event in translation, influenced by mRNA structures like slippery sequences.
- Mechanisms of programmed -1 frameshifting remain unclear despite extensive research.
Purpose of the Study:
- To elucidate the mechanistic and conformational dynamics of ribosomes during -1 frameshifting.
- To investigate ribosome behavior at individual codons during frameshift-inducing mRNA translation.
Main Methods:
- Single-molecule fluorescence microscopy was used to track ribosome dynamics.
- Analysis of ribosome pausing, subunit rotation, and tRNA interactions during translation of Escherichia coli dnaX mRNA.
Main Results:
- Frameshifted ribosomes exhibited a tenfold longer pause compared to non-frameshifted ribosomes.
- Ribosome-mRNA interactions during the pause uncoupled translocation and subunit rotation, creating a non-canonical state.
- tRNA sampling and EF-G action at the A site determined frameshifting into the -1 frame or continuation in the 0 frame.
Conclusions:
- A mechanistic and conformational framework for -1 ribosomal frameshifting was established.
- Multiple kinetic branchpoints during elongation were identified as crucial for frameshifting.
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