Characterization of ATPase Activity of Free and Immobilized Chromatophore Membrane Vesicles of Rhodobacter sphaeroides

2017 ◽  
Vol 27 (12) ◽  
pp. 2173-2179 ◽  
Author(s):  
Hyeonjun Kim ◽  
Xiaomeng Tong ◽  
Sungyoung Choi ◽  
Jeong K. Lee
Keyword(s):  
Atpase Activity ◽  
Rhodobacter Sphaeroides ◽  
Membrane Vesicles ◽  
Chromatophore Membrane

Electrophysiological Characterization of Transport Across Outer Membrane Channels from Gram-Negative Bacteria in Their Native Environment

2019 ◽  
Author(s):  
Jiajun Wang ◽  
Rémi Terrasse ◽  
Jayesh Arun Bafna ◽  
Lorraine Benier ◽  
Mathias Winterhalter
Keyword(s):  
Outer Membrane ◽  
Lipid Membrane ◽  
Membrane Vesicles ◽  
Outer Membrane Vesicles ◽  
Multi Drug Resistance ◽  
Gram Negative Bacteria ◽  
Membrane Channels ◽  
Gram Negative ◽  
Electrophysiological Characterization

Multi-drug resistance in Gram-negative bacteria is often associated with low permeability of the outer membrane. To investigate the role of membrane channels in the uptake of antibiotics, we extract, purify and reconstitute them into artificial planar membranes. To avoid this time-consuming procedure, here we show a robust approach using fusion of native outer membrane vesicles (OMV) into planar lipid bilayer which moreover allows also to some extend the characterization of membrane protein channels in their native environment. Two major membrane channels from <i>Escherichia coli</i>, OmpF and OmpC, were overexpressed from the host and the corresponding OMVs were collected. Each OMV fusion revealed surprisingly single or only few channel activities. The asymmetry of the OMV´s translates after fusion into the lipid membrane with the LPS dominantly present at the side of OMV addition. Compared to conventional reconstitution methods, the channels fused from OMVs containing LPS have similar conductance but a much broader distribution. The addition of Enrofloxacin on the LPS side yields somewhat higher association (<i>k<sub>on</sub></i>) and lower dissociation (<i>k<sub>off</sub></i>) rates compared to LPS-free reconstitution. We conclude that using outer membrane vesicles is a fast and easy approach for functional and structural studies of membrane channels in the native membrane.

scholarly journals Characterization of verapamil binding sites in cardiac membrane vesicles.

1984 ◽  
Vol 259 (24) ◽  
pp. 15013-15016 ◽  
Author(s):  
M L Garcia ◽  
M J Trumble ◽  
J P Reuben ◽  
G J Kaczorowski
Keyword(s):  
Binding Sites ◽  
Membrane Vesicles ◽  
Cardiac Membrane
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