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Co-Translational Insertion of Membrane Proteins into Preformed Nanodiscs
Published on: November 19, 2020
Post-translational membrane insertion of an endogenous YidC substrate
Philip J Robinson1, Cheryl A Woolhead1
1Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK.
Biochimica Et Biophysica Acta
|July 23, 2013
Summary
This study demonstrates that YidC acts as a post-translational insertase for bacterial inner membrane proteins, specifically the F0c subunit. This finding supports YidC
Area of Science:
- Biochemistry
- Molecular Biology
- Membrane Protein Biogenesis
Background:
- Bacterial inner membrane protein insertion primarily uses the Sec translocon.
- Some proteins insert independently of Sec, relying solely on YidC.
- YidC substrates often expose signal anchor sequences late in translation, suggesting post-translational insertion, though direct evidence is limited.
Purpose of the Study:
- To investigate the post-translational insertion activity of YidC.
- To develop an experimental system to uncouple translation and insertion of YidC substrates.
- To analyze the structure of YidC-inserted proteins.
Main Methods:
- Developed a one-step purification method for YidC with on-column membrane reconstitution.
- Isolated a soluble form of the F0c subunit, an endogenous YidC substrate.
- Incubated F0c with YidC proteoliposomes and analyzed integration using Blue Native PAGE and fluorescence quenching.
Main Results:
- Successfully purified YidC and reconstituted it into proteoliposomes.
- Isolated soluble F0c and demonstrated its high-level integration into YidC proteoliposomes.
- Conformational analyses confirmed that inserted F0c adopts a native, oligomerized structure.
Conclusions:
- YidC functions as a post-translational membrane protein insertase.
- This activity explains the lack of a ribosome-binding domain in YidC.
- Findings align with the known post-translational mechanisms of other YidC family members.
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