20-kDa accessory protein (P20) from Bacillus thuringiensis subsp. israelensis ISPC-12: Purification,
Omkar U Kinkar1, Rahul Singh1, Arpit Prashar2
1Homi Bhabha National Institute, Anushaktinagar, Mumbai 400094, Maharashtra, India; Beamline Development and Application Section, Bhabha Atomic Research Centre, Mumbai 400085, Maharashtra, India.
International Journal of Biological Macromolecules
|November 10, 2023
Summary
The Bacillus thuringiensis accessory protein P20 acts as a molecular chaperone, enhancing toxin production and insecticidal activity. This study characterizes P20, revealing its dimeric structure and role within the cytolytic toxin family.
Area of Science:
- Microbiology
- Molecular Biology
- Biochemistry
Background:
- The 20-kDa accessory protein (P20) from Bacillus thuringiensis subsp. israelensis (Bti) is a poorly understood molecular chaperone.
- P20 enhances the production and bio-crystallization of Cry11Aa and Cyt1Aa toxins, suppresses Cyt toxin's host toxicity, and boosts Cry1Ac insecticidal activity.
Purpose of the Study:
- To recombinantly express and purify P20 from Bti ISPC-12.
- To biochemically and biophysically characterize P20.
- To elucidate the structure and function of P20.
Main Methods:
- Recombinant expression of p20 in E. coli.
- Protein purification to homogeneity.
- Biochemical and biophysical characterization (including structural modeling and solution scattering).
Main Results:
- P20 was successfully expressed, purified, and characterized in vitro.
- Structural analysis revealed P20 is a non-toxic Cyt toxin family member with a conserved cytolysin fold.
- Solution scattering indicated P20 exists as a dimer, and a probable dimeric assembly was proposed.
Conclusions:
- This study provides crucial insights into the in-vitro behavior, spatial conformation, and dimeric structure of P20.
- The findings advance the understanding of P20's unique chaperone-like functions and its relationship to cytolytic toxins.
- Further research on P20 is expedited by these characterizations.
Keywords:
Bacillus thuringiensis subsp. israelensisCharacterizationCytolytic (Cyt) toxinsP20Structural modellingX-ray scattering
