Cryo-EM analysis of the <i>Bacillus thuringiensis</i> extrasporal matrix identifies F-ENA as a widespread family of endospore appendages across the Firmicutes phylum.

ABSTRACT: For over 100 years, Bacillus thuringiensis (Bt) has been used as an agricultural biopesticide to control pests caused by insect species in the orders of Lepidoptera, Diptera and Coleoptera. Under nutrient starvation, Bt cells differentiate into spores and associated toxin crystals that can adopt biofilm-like aggregates. We reveal that such Bt spore/toxin biofilms are embedded in a fibrous extrasporal matrix (ESM), and using cryoID, we resolved the structure and molecular identity of an uncharacterized type of pili, referred to here as Fibrillar ENdospore Appendages or 'F-ENA'. F-ENA are monomolecular protein polymers tethered to the exosporium of Bt and are decorated with a flexible tip fibrillum. Phylogenetic analysis reveals that F-ENA is widespread not only in the class Bacilli,

SUBMITTER: Sleutel M 

PROVIDER: S-EPMC11844507 | biostudies-literature | 2025 Feb

REPOSITORIES: biostudies-literature