Millisecond-Long Simulations of Antibiotics Transport through Outer Membrane Channels

2020 ◽  
Author(s):  
Vinaya Kumar Golla ◽  
Jigneshkumar Dahyabhai Prajapati ◽  
Ulrich Kleinekathöfer
Keyword(s):  
Outer Membrane ◽  
Membrane Channels

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 Differential Regulation of Two Oligogalacturonate Outer Membrane Channels, KdgN and KdgM, of Dickeya dadantii (Erwinia chrysanthemi)

2007 ◽  
Vol 189 (16) ◽  
pp. 5955-5962 ◽  
Author(s):  
Guy Condemine ◽  
Alexandre Ghazi
Keyword(s):  
Outer Membrane ◽  
Virulence Genes ◽  
Outer Membrane Proteins ◽  
Differential Regulation ◽  
Erwinia Chrysanthemi ◽  
Membrane Channels ◽  
Rich Medium ◽  
Positive Potential ◽  
Dickeya Dadantii ◽  
Opposite Manner

ABSTRACT The entry of oligogalacturonates into Dickeya dadantii occurs through the specific channel KdgM. The genome of the bacterium encodes a second member of this family of outer membrane proteins, KdgN. We showed that this protein is also involved in the uptake of oligogalacturonates. When KdgN was reconstituted in proteoliposomes, it formed channels with a conductance of about 450 pS at a positive potential. These channels had weak anionic selectivity. The regulation of kdgN is complex, and five genes controlling the expression of kdgN have been identified: kdgR, pecS, ompR, hns, and crp. Moreover, kdgN was regulated by growth phase but only when bacteria were grown in rich medium. Most of these regulators of kdgN also control kdgM expression, but some of them regulate kdgM in the opposite manner: while PecS and OmpR are repressors of kdgM, they are activators of kdgN. This pattern resembles the regulation of the Escherichia coli general porins OmpF and OmpC, but such opposite regulation of two specific outer membrane channels has never been described before. KdgN may allow the bacteria to collect oligogalacturonates under saprophytic conditions, when virulence genes, including kdgM, are not expressed.

scholarly journals Biophysical Insight into the Substrate Permeation through the Major Outer Membrane Channels of Acinetobacter baumannii

2017 ◽  
Vol 112 (3) ◽  
pp. 414a
Author(s):  
Satya Prathyusha Bhamidimarri ◽  
Michael Zahn ◽  
Jigneshkumar Dahyabhai Prajapati ◽  
Ulrich Kleinekathoefer ◽  
Bert van den Berg ◽  
...  
Keyword(s):  
Acinetobacter Baumannii ◽  
Outer Membrane ◽  
Membrane Channels ◽  
Insight Into

scholarly journals Outer Membrane Channels and Active Transporters for the Uptake of Antibiotics

2001 ◽  
Vol 183 (s1) ◽  
pp. S12-S16 ◽  
Author(s):  
Volkmar Braun ◽  
Christoph Bös ◽  
Michael Braun ◽  
Helmut Killmann
Keyword(s):  
Outer Membrane ◽  
Membrane Channels

scholarly journals Towards In-Silica Screening of Molecule Permeation through Outer Membrane Channels in Gramm-Negative Bacteria

2017 ◽  
Vol 112 (3) ◽  
pp. 291a
Author(s):  
Igor V. Bodrenko ◽  
Silvia Acosta-Gutierrez ◽  
Tommaso D’Agostino ◽  
Samuele Salis ◽  
Susruta Samanta ◽  
...  
Keyword(s):  
Outer Membrane ◽  
Membrane Channels
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