The structure of the flagellar hook junction protein HAP1 (FlgK) from Campylobacter jejuni

Experimental Data Snapshot

  • Resolution: 2.45 Å
  • R-Value Free: 0.232 
  • R-Value Work: 0.178 
  • R-Value Observed: 0.183 

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Structure of FlgK reveals the divergence of the bacterial Hook-Filament Junction of Campylobacter

Bulieris, P.V.Shaikh, N.H.Freddolino, P.L.Samatey, F.A.

(2017) Sci Rep 7: 15743-15743

  • DOI: https://doi.org/10.1038/s41598-017-15837-0
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    Evolution of a nano-machine consisting of multiple parts, each with a specific function, is a complex process. A change in one part should eventually result in changes in other parts, if the overall function is to be conserved. In bacterial flagella, the filament and the hook have distinct functions and their respective proteins, FliC and FlgE, have different three-dimensional structures. The filament functions as a helical propeller and the hook as a flexible universal joint. Two proteins, FlgK and FlgL, assure a smooth connectivity between the hook and the filament. Here we show that, in Campylobacter, the 3D structure of FlgK differs from that of its orthologs in Salmonella and Burkholderia, whose structures have previously been solved. Docking the model of the FlgK junction onto the structure of the Campylobacter hook provides some clues about its divergence. These data suggest how evolutionary pressure to adapt to structural constraints, due to the structure of Campylobacter hook, causes divergence of one element of a supra-molecular complex in order to maintain the function of the entire flagellar assembly.

  • Organizational Affiliation

    Trans-membrane Trafficking Unit, Okinawa Institute of Science and Technology Graduate University, 1919-1 Tancha, Onna, Kunigami, Okinawa, 904-0495, Japan.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Flagellar hook-associated protein FlgK511Campylobacter jejuniMutation(s): 0 
Find proteins for Q0P8E9 (Campylobacter jejuni subsp. jejuni serotype O:2 (strain ATCC 700819 / NCTC 11168))
Explore Q0P8E9 
Go to UniProtKB:  Q0P8E9
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ0P8E9
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 2.45 Å
  • R-Value Free: 0.232 
  • R-Value Work: 0.178 
  • R-Value Observed: 0.183 
  • Space Group: P 21 21 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 49.501α = 90
b = 123.552β = 90
c = 92.54γ = 90
Software Package:
Software NamePurpose
HKL-2000data reduction
HKL-2000data scaling

Structure Validation

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Entry History & Funding Information

Deposition Data

Funding OrganizationLocationGrant Number
Okinawa Institute of Science and Technology Graduate UniversityJapan--

Revision History  (Full details and data files)

  • Version 1.0: 2017-12-06
    Type: Initial release
  • Version 1.1: 2023-11-22
    Changes: Data collection, Database references, Refinement description