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Modulating co-translational protein folding by rational design and ribosome engineering
Minkoo Ahn1, Tomasz Włodarski1, Alkistis Mitropoulou1
1Institute of Structural and Molecular Biology, University College London, Gower Street, London, WC1E 6BT, UK.
Nature Communications
|July 22, 2022
Summary
Ribosome exit tunnel loops modulate protein folding during synthesis. Engineering these loops alters folding energetics, offering insights into controlling protein biosynthesis.
Area of Science:
- Molecular Biology
- Structural Biology
- Biophysics
Background:
- Co-translational folding is essential for nascent polypeptide biosynthesis as they emerge from the ribosome.
- The ribosome exit tunnel's structure influences how proteins fold during synthesis.
Purpose of the Study:
- To investigate how ribosome exit tunnel protein loop variations affect co-translational folding.
- To understand the role of tunnel shape and surface in modulating protein folding energetics.
Main Methods:
- Engineered ribosome exit tunnel loops (uL22, uL23, uL24) using CRISPR/Cas9 gene editing.
- Studied co-translational folding of a filamin domain (FLN5) using NMR spectroscopy.
- Utilized cryo-electron microscopy (cryo-EM) and molecular dynamics simulations.
Main Results:
- Thermodynamics measurements revealed how loop length variations impact FLN5 folding free energy.
- The interplay between uL23 and uL24 loops significantly alters co-translational folding energetics.
- Loop extensions led to opposite folding outcomes, demonstrating modulation capabilities.
Conclusions:
- Ribosome exit tunnel structure plays a crucial role in co-translational folding.
- Steric effects, dynamic interactions, and altered exit pathways contribute to folding modulation.
- Provides principles for engineering ribosome exit tunnels to control protein folding outcomes.
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