Characterization of the nucleoside-binding site inside the Tsx channel of Escherichia coli outer membrane Reconstitution experiments with lipid bilayer membranes

1988 ◽  
Vol 176 (3) ◽  
pp. 699-705 ◽  
Author(s):  
Roland BENZ ◽  
Angela SCHMID ◽  
Christl MAIER ◽  
Erhard BREMER
Keyword(s):  
Escherichia Coli ◽  
Binding Site ◽  
Outer Membrane ◽  
Lipid Bilayer ◽  
Lipid Bilayer Membranes ◽  
Bilayer Membranes ◽  
Membrane Reconstitution

scholarly journals Evaluation of the rate constants of sugar transport through maltoporin (LamB) of Escherichia coli from the sugar-induced current noise.

1995 ◽  
Vol 105 (3) ◽  
pp. 385-401 ◽  
Author(s):  
C Andersen ◽  
M Jordy ◽  
R Benz
Keyword(s):  
Escherichia Coli ◽  
Binding Site ◽  
Outer Membrane ◽  
Rate Constants ◽  
Sugar Transport ◽  
Current Noise ◽  
Induced Current ◽  
Lipid Bilayer Membranes ◽  
Sugar Binding ◽  
Different Temperatures

LamB (maltoporin) of Escherichia coli outer membrane was reconstituted into artificial lipid bilayer membranes. The channel contains a binding site for sugars and is blocked for ions when the site is occupied by a sugar. The on and off reactions of sugar binding cause an increase of the noise of the current through the channel. The sugar-induced current noise of maltoporin was used for the evaluation of the sugar-binding kinetics for different sugars of the maltooligosaccharide series and for sucrose. The on rate constant for sugar binding was between 10(6) and 10(7) M-1.s-1 for the maltooligosaccharides and corresponds to the movement of the sugars from the aqueous phase to the central binding site. The off rate (corresponding to the release of the sugars from the channel) decreased with increasing number of glucose residues in the maltooligosaccharides from approximately 2,000 s-1 for maltotriose to 180 s-1 for maltoheptaose. The kinetics for sucrose movement was considerably slower. The activation energies of the stability constant and of the rate constants for sugar binding were evaluated from noise experiments at different temperatures. The role of LamB in the transport of maltooligosaccharides across the outer membrane is discussed.

scholarly journals Reconstitution of bacterial outer membrane TonB-dependent transporters in planar lipid bilayer membranes

2009 ◽  
Vol 106 (51) ◽  
pp. 21990-21995 ◽  
Author(s):  
E. Udho ◽  
K. S. Jakes ◽  
S. K. Buchanan ◽  
K. J. James ◽  
X. Jiang ◽  
...  
Keyword(s):  
Outer Membrane ◽  
Lipid Bilayer ◽  
Planar Lipid Bilayer ◽  
Lipid Bilayer Membranes ◽  
Bilayer Membranes ◽  
Bacterial Outer Membrane
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