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Updated: Sep 12, 2025
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DNA-Tethered RNA Polymerase for Programmable In vitro Transcription and Molecular Computation
Published on: December 29, 2021
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Reversible DNA condensation drives natural transformation
Biorxiv : the Preprint Server for Biology
|August 6, 2025
Summary
Bacterial DNA receptor ComEA uses dynamic oligomers to pull transforming DNA into the cell. This process is crucial for spreading antibiotic resistance and involves reversible DNA condensation and decondensation.
Area of Science:
- Microbiology
- Molecular Biology
- Biophysics
Background:
- Natural transformation is a key mechanism for bacterial genetic exchange and the spread of antibiotic resistance.
- The DNA receptor ComEA plays a vital role in importing external DNA into the bacterial periplasm, but its mechanism remains unclear.
Purpose of the Study:
- To elucidate the mechanism by which ComEA facilitates DNA uptake during natural transformation.
- To investigate the structural dynamics of ComEA on DNA and its role in force generation.
Main Methods:
- Single-molecule optical tweezers were employed to measure forces exerted by ComEA on DNA.
- Electron microscopy was used to visualize ComEA-DNA complexes.
- Mutational analysis in *Bacillus subtilis* assessed the functional importance of ComEA conformations.
Main Results:
- ComEA forms dynamic oligomers on DNA that switch between bridging and non-bridging conformations based on local concentration.
- Bridging oligomers condense DNA and generate sub-piconewton pulling forces, essential for periplasmic import.
- Non-bridging oligomers decondense DNA and do not generate force, facilitating cytoplasmic transport.
Conclusions:
- ComEA utilizes reversible DNA condensation and decondensation to drive DNA transport during natural transformation.
- Both force generation (condensation) and force abatement (decondensation) by ComEA are essential for successful transformation.
- Understanding ComEA's mechanism provides insights into bacterial genetic exchange and antibiotic resistance dissemination.
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