Permeabilization of Model Lipid Membranes by Bacillus sphaericus Mosquitocidal Binary Toxin and its Individual Components

Permeabilization of Model Lipid Membranes by Bacillus sphaericus Mosquitocidal Binary Toxin and... The high larvicidal effect of Bacillus sphaericus (Bs), a mosquito control agent, originates from the presence of a binary toxin (Bs Bin) composed of two proteins (BinA and BinB) that work together to lyse gut cells of susceptible larvae. We demonstrate for the first time that the binary toxin and its individual components permeabilize receptor-free large unilamellar phospholipid vesicles (LUVs) and planar lipid bilayers (PLBs) by a mechanism of pore formation. Calcein-release experiments showed that LUV permeabilization was optimally achieved at alkaline pH and in the presence of acidic lipids. BinA was more efficient than BinB, BinB facilitated the BinA effect, and their stoichiometric mixture was more effective than the full Bin toxin. In PLBs, BinA formed voltage-dependent channels of ≈100–200 pS with long open times and a high open probability. Larger channels (≥400 pS) were also observed. BinB, which inserted less easily, formed smaller channels (≤100 pS) with shorter mean open times. Channels observed after sequential addition of the two components, or formed by their 1:1 mixture (w/w), displayed BinA-like activity. Bs Bin toxin was less efficient at forming channels than the BinA/BinB mixture, with channels displaying the BinA channel behavior. Our data support the concept of BinA being principally responsible for pore formation in lipid membranes with BinB, the binding component of the toxin, playing a role in promoting channel activity. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png The Journal of Membrane Biology Springer Journals

Permeabilization of Model Lipid Membranes by Bacillus sphaericus Mosquitocidal Binary Toxin and its Individual Components

Loading next page...
 
/lp/springer_journal/permeabilization-of-model-lipid-membranes-by-bacillus-sphaericus-vCBDwQNrM0
Publisher
Springer-Verlag
Copyright
Copyright © Inc. by 2001 Springer-Verlag New York
Subject
Life Sciences; Biochemistry, general; Human Physiology
ISSN
0022-2631
eISSN
1432-1424
D.O.I.
10.1007/s00232-001-0086-1
Publisher site
See Article on Publisher Site

Abstract

The high larvicidal effect of Bacillus sphaericus (Bs), a mosquito control agent, originates from the presence of a binary toxin (Bs Bin) composed of two proteins (BinA and BinB) that work together to lyse gut cells of susceptible larvae. We demonstrate for the first time that the binary toxin and its individual components permeabilize receptor-free large unilamellar phospholipid vesicles (LUVs) and planar lipid bilayers (PLBs) by a mechanism of pore formation. Calcein-release experiments showed that LUV permeabilization was optimally achieved at alkaline pH and in the presence of acidic lipids. BinA was more efficient than BinB, BinB facilitated the BinA effect, and their stoichiometric mixture was more effective than the full Bin toxin. In PLBs, BinA formed voltage-dependent channels of ≈100–200 pS with long open times and a high open probability. Larger channels (≥400 pS) were also observed. BinB, which inserted less easily, formed smaller channels (≤100 pS) with shorter mean open times. Channels observed after sequential addition of the two components, or formed by their 1:1 mixture (w/w), displayed BinA-like activity. Bs Bin toxin was less efficient at forming channels than the BinA/BinB mixture, with channels displaying the BinA channel behavior. Our data support the concept of BinA being principally responsible for pore formation in lipid membranes with BinB, the binding component of the toxin, playing a role in promoting channel activity.

Journal

The Journal of Membrane BiologySpringer Journals

Published: Nov 15, 2001

There are no references for this article.

You’re reading a free preview. Subscribe to read the entire article.


DeepDyve is your
personal research library

It’s your single place to instantly
discover and read the research
that matters to you.

Enjoy affordable access to
over 18 million articles from more than
15,000 peer-reviewed journals.

All for just $49/month

Explore the DeepDyve Library

Search

Query the DeepDyve database, plus search all of PubMed and Google Scholar seamlessly

Organize

Save any article or search result from DeepDyve, PubMed, and Google Scholar... all in one place.

Access

Get unlimited, online access to over 18 million full-text articles from more than 15,000 scientific journals.

Your journals are on DeepDyve

Read from thousands of the leading scholarly journals from SpringerNature, Elsevier, Wiley-Blackwell, Oxford University Press and more.

All the latest content is available, no embargo periods.

See the journals in your area

DeepDyve

Freelancer

DeepDyve

Pro

Price

FREE

$49/month
$360/year

Save searches from
Google Scholar,
PubMed

Create lists to
organize your research

Export lists, citations

Read DeepDyve articles

Abstract access only

Unlimited access to over
18 million full-text articles

Print

20 pages / month

PDF Discount

20% off