Single-channel analysis of the conductance fluctuations induced in lipid bilayer membranes by complement proteins C5b-9

1986 ◽  
Vol 94 (1) ◽  
pp. 37-45 ◽  
Author(s):  
Roland Benz ◽  
Angela Schmid ◽  
Therese Wiedmer ◽  
Peter J. Sims
Keyword(s):  
Lipid Bilayer ◽  
Single Channel ◽  
Lipid Bilayer Membranes ◽  
Bilayer Membranes ◽  
Complement Proteins ◽  
Conductance Fluctuations ◽  
Single Channel Analysis ◽  
Channel Analysis

scholarly journals Alamethicin channels incorporated into frog node of ranvier: calcium-induced inactivation and membrane surface charges.

1982 ◽  
Vol 79 (3) ◽  
pp. 411-436 ◽  
Author(s):  
M D Cahalan ◽  
J Hall
Keyword(s):  
Lipid Bilayer ◽  
Surface Potential ◽  
Single Channel ◽  
Membrane Surface ◽  
Internal Surface ◽  
Peptide Antibiotic ◽  
Lipid Bilayer Membranes ◽  
Surface Charges ◽  
Myelinated Nerve ◽  
Bilayer Membranes

Alamethicin, a peptide antibiotic, partitions into artificial lipid bilayer membranes and into frog myelinated nerve membranes, inducing a voltage-dependent conductance. Discrete changes in conductance representing single-channel events with multiple open states can be detected in either frog node or lipid bilayer membranes. In 120 mM salt solution, the average conductance of a single channel is approximately 600 pS. The channel lifetimes are roughly two times longer in the node membrane than in a phosphatidylethanolamine bilayer at the same membrane potential. With 2 or 20 mM external Ca and internal CsCl, the alamethicin-induced conductance of frog nodal membrane inactivates. Inactivation is abolished by internal EGTA, suggesting that internal accumulation of calcium ions is responsible for the inactivation, through binding of Ca to negative internal surface charges. As a probe for both external and internal surface charges, alamethicin indicates a surface potential difference of approximately -20 to -30 mV, with the inner surface more negative. This surface charge asymmetry is opposite to the surface potential distribution near sodium channels.

scholarly journals The C-Terminal Domain of the Bordetella pertussisAutotransporter BrkA Forms a Pore in Lipid Bilayer Membranes

1999 ◽  
Vol 181 (18) ◽  
pp. 5838-5842 ◽  
Author(s):  
Jennifer L. Shannon ◽  
Rachel C. Fernandez
Keyword(s):  
Outer Membrane ◽  
Lipid Bilayer ◽  
Single Channel ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Lipid Bilayer Membranes ◽  
Channel Conductance ◽  
Terminal Protein ◽  
Bilayer Membranes ◽  
Terminal Domain

ABSTRACT BrkA is a 103-kDa outer membrane protein of Bordetella pertussis that mediates resistance to antibody-dependent killing by complement. It is proteolytically processed into a 73-kDa N-terminal domain and a 30-kDa C-terminal domain as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. BrkA is also a member of the autotransporter family of proteins. Translocation of the N-terminal domain of the protein across the outer membrane is hypothesized to occur through a pore formed by the C-terminal domain. To test this hypothesis, we performed black lipid bilayer experiments with purified recombinant protein. The BrkA C-terminal protein showed an average single-channel conductance of 3.0 nS in 1 M KCl. This result strongly suggests that the C-terminal autotransporter domain of BrkA is indeed capable of forming a pore.

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