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From Constructs to Crystals – Towards Structure Determination of β-barrel Outer Membrane Proteins
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Influence of Membrane Asymmetry on OmpF Insertion, Orientation and Function
Annemarie Donoghue1,2, Mathias Winterhalter2, Thomas Gutsmann1,3
1Research Center Borstel, Leibniz Lung Center, Parkallee 10, 23845 Borstel, Germany.
Membranes
|May 26, 2023
Summary
Lipopolysaccharides (LPS) in asymmetric membranes significantly impact outer membrane protein F (OmpF) reconstitution and antibiotic permeation. Enrofloxacin antibiotic activity was modulated by LPS membrane phase behavior and OmpF channel function.
Area of Science:
- Biophysics
- Membrane Biology
- Drug Delivery
Background:
- Outer membrane proteins (OMPs) like OmpF are crucial for nutrient uptake and antibiotic entry in Gram-negative bacteria.
- Lipopolysaccharides (LPS) form the outer leaflet of the Gram-negative bacterial outer membrane, influencing its structure and function.
- Understanding OMP behavior in asymmetric lipid bilayers is vital for developing new antimicrobial strategies.
Purpose of the Study:
- To investigate the effect of asymmetric membranes containing LPS on OmpF reconstitution, channel orientation, and antibiotic permeation.
- To explore the interaction of the antibiotic enrofloxacin with OmpF in LPS-containing asymmetric membranes.
- To elucidate how LPS and antibiotic interactions influence membrane properties and OmpF channel function.
Main Methods:
- Formation of asymmetric planar lipid bilayers with LPS on one leaflet and phospholipids on the other.
- Incorporation and reconstitution of the outer membrane protein F (OmpF) into the asymmetric membrane.
- Ion current recordings to analyze OmpF channel activity, orientation, and gating.
- Investigation of enrofloxacin's effect on ion current, OmpF function, and LPS membrane phase behavior.
Main Results:
- LPS significantly influences OmpF membrane insertion, orientation, and gating.
- Enrofloxacin addition blocked ion current through OmpF in a manner dependent on addition side, voltage, and buffer composition.
- Enrofloxacin altered the phase behavior of LPS-containing membranes, indicating its interaction with the membrane affects OmpF function.
Conclusions:
- Asymmetric LPS-containing membranes modulate OmpF channel properties and antibiotic permeation.
- Enrofloxacin's interaction with LPS membranes affects OmpF function and potentially overall membrane permeability.
- This study provides insights into the complex interplay between membrane composition, OMPs, and antibiotic activity, relevant for drug development.
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