6X80

Structure of the Campylobacter jejuni G508A Flagellar Filament

Summary for 6X80

• Entry DOI: 10.2210/pdb6x80/pdb
• EMDB information: 22088
• Descriptor: Flagellin A, 5,7-diamino-3,5,7,9-tetradeoxy-L-glycero-alpha-L-manno-non-2-ulopyranosonic acid (2 entities in total)
• Functional Keywords: helical symmetry, bacterial flagellar filament, structural protein
• Biological source: Campylobacter jejuni
• Total number of polymer chains: 22
• Total formula weight: 1404589.89

Authors

Kreutzberger, M.A.B.,Wang, F.,Egelman, E.H. (deposition date: 2020-06-01, release date: 2020-07-08, Last modification date: 2025-06-04)

Primary citation

Kreutzberger, M.A.B.,Ewing, C.,Poly, F.,Wang, F.,Egelman, E.H.
Atomic structure of the Campylobacter jejuni flagellar filament reveals how epsilon Proteobacteria escaped Toll-like receptor 5 surveillance.
Proc.Natl.Acad.Sci.USA, 117:16985-16991, 2020

PubMed Abstract: Vertebrates, from zebra fish to humans, have an innate immune recognition of many bacterial flagellins. This involves a conserved eight-amino acid epitope in flagellin recognized by the Toll-like receptor 5 (TLR5). Several important human pathogens, such as and , have escaped TLR5 activation by mutations in this epitope. When such mutations were introduced into flagellin, motility was abolished. It was previously argued, using very low-resolution cryoelectron microscopy (cryo-EM), that accommodated these mutations by forming filaments with 7 protofilaments, rather than the 11 found in other bacteria. We have now determined the atomic structure of the G508A flagellar filament from a 3.5-Å-resolution cryo-EM reconstruction, and show that it has 11 protofilaments. The residues in the TLR5 epitope have reduced contacts with the adjacent subunit compared to other bacterial flagellar filament structures. The weakening of the subunit-subunit interface introduced by the mutations in the TLR5 epitope is compensated for by extensive interactions between the outer domains of the flagellin subunits. In other bacteria, these outer domains can be nearly absent or removed without affecting motility. Furthermore, we provide evidence for the stabilization of these outer domain interactions through glycosylation of key residues. These results explain the essential role of glycosylation in motility, and show how the outer domains have evolved to play a role not previously found in other bacteria.

PubMed: 32641510
DOI: 10.1073/pnas.2010996117

Experimental method

ELECTRON MICROSCOPY (3.5 Å)