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Updated: Jul 22, 2025
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High-resolution Single Particle Analysis from Electron Cryo-microscopy Images Using SPHIRE
Published on: May 16, 2017
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Cry11Aa and Cyt1Aa exhibit different structural orders in crystal topography.
Shu-Wen W Chen1,2, Jean-Marie Teulon1, Jean-Luc Pellequer1
1Univ. Grenoble Alpes, CEA, CNRS, Institut de Biologie Structurale (IBS), Grenoble, France.
Journal of Molecular Recognition : JMR
|July 20, 2023
Summary
Atomic force microscopy revealed distinct structural features of Bacillus thuringiensis toxins. Cry11Aa toxins show a higher potential for multimerization, suggesting enhanced cooperative toxic actions compared to Cyt1Aa.
Area of Science:
- Microbiology
- Biochemistry
- Toxicology
Background:
- Bacillus thuringiensis subsp. israelensis produces pesticidal Cry11Aa and Cyt1Aa toxins.
- Understanding toxin oligomerization is crucial for elucidating their toxic mechanisms and synergistic effects.
Purpose of the Study:
- To investigate the oligomeric states of Cry11Aa and Cyt1Aa toxins.
- To explore the structural basis for potential synergistic toxic actions.
Main Methods:
- Atomic force microscopy (AFM) was employed to analyze the surface topography of natively grown Cry11Aa and Cyt1Aa crystals.
- L-weight filtering was utilized to enhance structural details within the AFM data.
Main Results:
- AFM analysis, enhanced by L-weight filtering, provided molecular sizes for Cry11Aa and Cyt1Aa monomers consistent with X-ray crystallography data.
- Distinct topographic characteristics were observed, with Cry11Aa crystals exhibiting a layered feature.
- This layered structure suggests a greater propensity for Cry11Aa multimerization compared to Cyt1Aa.
Conclusions:
- Cry11Aa toxins possess structural attributes favoring multimerization.
- Enhanced multimerization of Cry11Aa may lead to more cooperative toxic actions, potentially explaining synergistic effects.
- The findings provide insights into the structural basis of Bacillus thuringiensis toxin activity.
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