5KYH

Structure of Iho670 Flagellar-like Filament

Summary for 5KYH

• Entry DOI: 10.2210/pdb5kyh/pdb
• Related: 3J1R
• EMDB information: 5423 8298
• Descriptor: Iho670 (1 entity in total)
• Functional Keywords: immunoglobulin fold, type iv pili, flagellin, cell adhesion
• Biological source: Ignicoccus hospitalis
• Total number of polymer chains: 21
• Total formula weight: 682952.32

Authors

Braun, T.,Vos, M.,Kalisman, N.,Sherman, N.E.,Rachel, R.,Wirth, R.,Schroeder, G.F.,Egelman, E.H. (deposition date: 2016-07-21, release date: 2016-09-07, Last modification date: 2024-11-13)

Primary citation

Braun, T.,Vos, M.R.,Kalisman, N.,Sherman, N.E.,Rachel, R.,Wirth, R.,Schroder, G.F.,Egelman, E.H.
Archaeal flagellin combines a bacterial type IV pilin domain with an Ig-like domain.
Proc.Natl.Acad.Sci.USA, 113:10352-10357, 2016

PubMed Abstract: The bacterial flagellar apparatus, which involves ∼40 different proteins, has been a model system for understanding motility and chemotaxis. The bacterial flagellar filament, largely composed of a single protein, flagellin, has been a model for understanding protein assembly. This system has no homology to the eukaryotic flagellum, in which the filament alone, composed of a microtubule-based axoneme, contains more than 400 different proteins. The archaeal flagellar system is simpler still, in some cases having ∼13 different proteins with a single flagellar filament protein. The archaeal flagellar system has no homology to the bacterial one and must have arisen by convergent evolution. However, it has been understood that the N-terminal domain of the archaeal flagellin is a homolog of the N-terminal domain of bacterial type IV pilin, showing once again how proteins can be repurposed in evolution for different functions. Using cryo-EM, we have been able to generate a nearly complete atomic model for a flagellar-like filament of the archaeon Ignicoccus hospitalis from a reconstruction at ∼4-Å resolution. We can now show that the archaeal flagellar filament contains a β-sandwich, previously seen in the FlaF protein that forms the anchor for the archaeal flagellar filament. In contrast to the bacterial flagellar filament, where the outer globular domains make no contact with each other and are not necessary for either assembly or motility, the archaeal flagellin outer domains make extensive contacts with each other that largely determine the interesting mechanical properties of these filaments, allowing these filaments to flex.

PubMed: 27578865
DOI: 10.1073/pnas.1607756113

Experimental method

ELECTRON MICROSCOPY (4 Å)