Related Experiment Videos
The staphylococcal alpha-toxin pore has a flexible conformation.
B Vécsey-Semjén1, S Knapp, R Möllby
1Microbiology and Tumorbiology Center, Karolinska Institutet, Stockholm, Sweden.
Biochemistry
|April 9, 1999
Summary
Staphylococcus aureus alpha-toxin
Area of Science:
- Microbiology
- Biochemistry
- Structural Biology
Background:
- Staphylococcus aureus alpha-toxin is a pore-forming protein.
- It undergoes conformational changes to form a channel in host cell membranes.
Purpose of the Study:
- To analyze the stability of different forms of alpha-toxin.
- To understand the structural conformation of the membrane-inserted channel.
Main Methods:
- Differential scanning calorimetry (DSC).
- Limited proteolysis.
- Far-UV circular dichroism (CD) spectroscopy.
Main Results:
- The membrane-inserted alpha-toxin channel is less stable and more susceptible to proteases than monomeric or prepore forms.
- Protease resistance is regained upon solubilization, indicating conformational changes during membrane insertion.
- The beta-barrel structure is stable, but Cap and Rim domains are loosely packed in the membrane.
Conclusions:
- The alpha-toxin channel adopts a flexible conformation within the membrane, not a rigid structure.
- This flexibility may be crucial for channel function and interaction with the lipid bilayer.