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Updated: Jun 17, 2026
08:21
Site-specific Bacterial Chromosome Engineering: ΦC31 Integrase Mediated Cassette Exchange (IMCE)
Published on: March 16, 2012
Composite system mediates two-step DNA uptake into Helicobacter pylori
Kerstin Stingl1, Stephanie Müller, Gerda Scheidgen-Kleyboldt
1Westfälische Wilhelms-Universität, Institut für Allgemeine Zoologie und Genetik, 48149 Münster, Germany. k.stingl@web.de
Summary
Helicobacter pylori uses a two-step DNA uptake system involving ComB and ComEC. This process facilitates genomic plasticity and host adaptation in this important bacterial pathogen.
Area of Science:
- Microbiology
- Genetics
- Molecular Biology
Background:
- Helicobacter pylori is a Gram-negative bacterium crucial for genomic plasticity.
- Natural transformation in H. pylori aids host adaptation and resistance spread.
Purpose of the Study:
- To elucidate the mechanism of DNA uptake in H. pylori.
- To identify the roles of ComB and ComEC in DNA transport.
Main Methods:
- Utilized covalently labeled fluorescent DNA for uptake studies.
- Employed pH titration and proton accessibility assays to localize DNA.
- Performed single-molecule analysis to determine DNA transport velocity and forces.
- Investigated DNA uptake in wild-type and ComEC-deficient H. pylori mutants.
Main Results:
- H. pylori preferentially takes up DNA at cell poles via the ComB type IV secretion system.
- Imported DNA was localized to the periplasm, with transport velocities of 1.3 kbp/s.
- DNA could be extracted at forces exceeding 23 pN, indicating lower stalling forces than Bacillus subtilis.
- dsDNA was transiently detected in the periplasm of wild-type but trapped in ComEC mutants.
Conclusions:
- H. pylori employs a two-step DNA uptake mechanism: ComB transports dsDNA across the outer membrane, and Hp-ComEC mediates cytoplasmic transport.
- This mechanism is conserved in competent bacteria, involving ComEC for cytoplasmic transport and diverse outer membrane transporters.
- Findings provide a model for composite DNA uptake machineries in bacteria.
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