Laboratorio Nacional de Microscopía Avanzada, Mexico (@lnma-mx.bsky.social)

Congratulations to LNMA member @AdanGue1 for his co-authorship on this fresh-off-the-pdfmaker Plos Pathogens article on receptor structural changes in insecticidal B. Thuringensis proteins, in collaboration with the Bravo-Soberón group at the @ibt_unam journals.plos.org/Pl...

loading . . .

Insights into the structural changes that trigger receptor binding upon proteolytic activation of Bacillus thuringiensis Vip3Aa insecticidal protein Author summary To exert toxicity, Vip3 tetrameric protoxins are activated by larval gut proteases facilitating the formation of lytic pores that destroy the midgut epithelium cells killing the susceptible larvae. Here, we demonstrate that the proteolytic activation of Vip3Aa protoxin is necessary for triggering receptor binding. Binding analysis of Vip3Aa protoxin and activated toxin to S. frugiperda midguts and toxicity assays against Sf9 cells, confirmed that proteolytic activation is necessary for an efficient binding to the insect midgut membranes and for toxicity. The analysis of residues from domains III, IV and V, that become exposed after Vip3Aa activation by proteolysis, allowed us to identify a structural binding epitope which plays an important role in receptor binding and toxicity. Our results indicate that the structural change that Vip3Aa undergoes after activation by larval midgut proteases, besides being important for membrane insertion and pore formation, also triggers receptor binding important for toxicity. https://journals.plos.org/Plospathogens/article?id=10.1371/journal.ppat.1012765