Bacillus thuringiensis toxin Cyt2Aa forms filamentous oligomers when exposed to lipid membranes or detergents

Šolinc, Gašper (avtor), Anderluh, Gregor (avtor), Podobnik, Marjetka (avtor)

The bacterium Bacillus thuringiensis (Bt) produces insecticidal proteins during the sporulation phase. These proteins are located in parasporal crystals consisting of two delta-endotoxin classes, crystal (Cry) and cytolytic (Cyt) toxins. In vitro, Cyt toxins show cytolytic activity against bacterial and a variety of insect and mammalian cells. They bind to cell membranes with unsaturated phospholipids and sphingomyelin. Although Bt and its parasporal crystals containing both Cry and Cyt toxins have been successfully used as bioinsecticides, the molecular mechanism of action of Cyt toxins is not yet fully understood. To address this, we exposed Cyt2Aa to lipid membranes and visualized membrane disruption process using cryo-electron microscopy. We observed two types of Cyt2Aa oligomers. First, Cyt2Aa forms smaller curved oligomers on the membrane surface that become linear over time, and detach when the membrane ruptures. Similar linear filamentous oligomers were also formed by Cyt2Aa in the presence of detergents without prior exposure to lipid membranes, which exhibited attenuated cytolytic activity. Furthermore, our data suggest that Cyt2Aa adopts different conformations between its monomeric and oligomeric forms. Overall, our results provide new evidence for a detergent-like mechanism of action of Cyt2Aa rather than the pore-forming model of target membrane disruption of this important class of insecticidal proteins.

• Jezik: Angleški jezik
• Ključne besede: Bacillus thuringiensis, parasporal crystal delta-endotoxins, Cyt toxin, Cyt2Aa, oligomers, detergent-like mechanism of action
• Vrsta gradiva: Članek v reviji
• Tipologija: 1.01 - Izvirni znanstveni članek
• Organizacija: BF - Biotehniška fakulteta
• Status publikacije: Objavljeno
• Različica publikacije: Objavljena publikacija
• Leto izida: 2023
• Št. strani: Str. 44-52
• Številčenje: Vol. 674
• PID: 20.500.12556/RUL-152844
• UDK: 577
• ISSN pri članku: 1090-2104
• DOI: 10.1016/j.bbrc.2023.06.078
• COBISS.SI-ID: 158413827
• Datum objave v RUL: 08.12.2023

Gradivo je del revije

• Naslov: Biochemical and biophysical research communications
• Skrajšan naslov: Biochem. biophys. res. commun.
• Založnik: Elsevier
• ISSN: 1090-2104
• COBISS.SI-ID: 18258983

Licence

• Licenca: CC BY-NC-ND 4.0, Creative Commons Priznanje avtorstva-Nekomercialno-Brez predelav 4.0 Mednarodna
• Povezava: http://creativecommons.org/licenses/by-nc-nd/4.0/deed.sl
• Opis: Najbolj omejujoča licenca Creative Commons. Uporabniki lahko prenesejo in delijo delo v nekomercialne namene in ga ne smejo uporabiti za nobene druge namene.

Sekundarni jezik

• Jezik: Slovenski jezik
• Ključne besede: biokemija, bakterije, bacili, toksini, lipidne membrane, oligomeri