7A02

Bacillus endospore appendages form a novel family of disulfide-linked pili

Summary for 7A02

• Entry DOI: 10.2210/pdb7a02/pdb
• EMDB information: 11591
• Descriptor: DUF3992 domain-containing protein (1 entity in total)
• Functional Keywords: pilli, endospore, gram-positive, helical reconstruction, disulphide bridge, unknown function
• Biological source: Bacillus cereus
• Total number of polymer chains: 23
• Total formula weight: 279741.52

Authors

Pradhan, B.,Liedtke, J.,Sleutel, M.,Lindback, T.,Llarena, A.K.,Brynildsrud, O.,Aspholm, M.,Remaut, H. (deposition date: 2020-08-06, release date: 2021-04-28, Last modification date: 2021-09-15)

Primary citation

Pradhan, B.,Liedtke, J.,Sleutel, M.,Lindback, T.,Zegeye, E.D.,O Sullivan, K.,Llarena, A.K.,Brynildsrud, O.,Aspholm, M.,Remaut, H.
Endospore Appendages: a novel pilus superfamily from the endospores of pathogenic Bacilli.
Embo J., 40:e106887-e106887, 2021

PubMed Abstract: Bacillus cereus sensu lato is a group of Gram-positive endospore-forming bacteria with high ecological diversity. Their endospores are decorated with micrometer-long appendages of unknown identity and function. Here, we isolate endospore appendages (Enas) from the food poisoning outbreak strain B. cereus NVH 0075-95 and find proteinaceous fibers of two main morphologies: S- and L-Ena. By using cryoEM and 3D helical reconstruction of S-Enas, we show these to represent a novel class of Gram-positive pili. S-Enas consist of single domain subunits with jellyroll topology that are laterally stacked by β-sheet augmentation. S-Enas are longitudinally stabilized by disulfide bonding through N-terminal connector peptides that bridge the helical turns. Together, this results in flexible pili that are highly resistant to heat, drought, and chemical damage. Phylogenomic analysis reveals a ubiquitous presence of the ena-gene cluster in the B. cereus group, which include species of clinical, environmental, and food importance. We propose Enas to represent a new class of pili specifically adapted to the harsh conditions encountered by bacterial spores.

PubMed: 34031903
DOI: 10.15252/embj.2020106887

Experimental method

ELECTRON MICROSCOPY (3 Å)