Crystal structure of the helical cell shape determining protein Pgp2 from Campylobacter jejuni

Experimental Data Snapshot

  • Resolution: 1.50 Å
  • R-Value Free: 0.192 
  • R-Value Work: 0.158 
  • R-Value Observed: 0.159 

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Peptidoglycan binding by a pocket on the accessory NTF2-domain of Pgp2 directs helical cell shape of Campylobacter jejuni.

Lin, C.S.Chan, A.C.K.Vermeulen, J.Brockerman, J.Soni, A.S.Tanner, M.E.Gaynor, E.C.McIntosh, L.P.Simorre, J.P.Murphy, M.E.P.

(2021) J Biol Chem 296: 100528-100528

  • DOI: https://doi.org/10.1016/j.jbc.2021.100528
  • Primary Citation of Related Structures:  
    6XJ6, 6XJ7

  • PubMed Abstract: 

    The helical morphology of Campylobacter jejuni, a bacterium involved in host gut colonization and pathogenesis in humans, is determined by the structure of the peptidoglycan (PG) layer. This structure is dictated by trimming of peptide stems by the LD-carboxypeptidase Pgp2 within the periplasm. The interaction interface between Pgp2 and PG to select sites for peptide trimming is unknown. We determined a 1.6 Å resolution crystal structure of Pgp2, which contains a conserved LD-carboxypeptidase domain and a previously uncharacterized domain with an NTF2-like fold (NTF2). We identified a pocket in the NTF2 domain formed by conserved residues and located ∼40 Å from the LD-carboxypeptidase active site. Expression of pgp2 in trans with substitutions of charged (Lys257, Lys307, Glu324) and hydrophobic residues (Phe242 and Tyr233) within the pocket did not restore helical morphology to a pgp2 deletion strain. Muropeptide analysis indicated a decrease of murotripeptides in the deletion strain expressing these mutants, suggesting reduced Pgp2 catalytic activity. Pgp2 but not the K307A mutant was pulled down by C. jejuni Δpgp2 PG sacculi, supporting a role for the pocket in PG binding. NMR spectroscopy was used to define the interaction interfaces of Pgp2 with several PG fragments, which bound to the active site within the LD-carboxypeptidase domain and the pocket of the NTF2 domain. We propose a model for Pgp2 binding to PG strands involving both the LD-carboxypeptidase domain and the accessory NTF2 domain to induce a helical cell shape.

  • Organizational Affiliation

    Department of Microbiology and Immunology, University of British Columbia, Vancouver, British Columbia, Canada.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Pgp2287Campylobacter jejuni subsp. jejuni 81-176Mutation(s): 0 
Gene Names: CJJ81176_0915
Find proteins for A0A0H3PAQ3 (Campylobacter jejuni subsp. jejuni serotype O:23/36 (strain 81-176))
Explore A0A0H3PAQ3 
Go to UniProtKB:  A0A0H3PAQ3
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupA0A0H3PAQ3
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 1.50 Å
  • R-Value Free: 0.192 
  • R-Value Work: 0.158 
  • R-Value Observed: 0.159 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 47.451α = 90
b = 71.942β = 90
c = 91.691γ = 90
Software Package:
Software NamePurpose
DENZOdata reduction
SCALEPACKdata scaling
PDB_EXTRACTdata extraction

Structure Validation

View Full Validation Report

Entry History & Funding Information

Deposition Data

Funding OrganizationLocationGrant Number
Canadian Institutes of Health Research (CIHR)Canada--

Revision History  (Full details and data files)

  • Version 1.0: 2021-03-17
    Type: Initial release
  • Version 1.1: 2021-03-24
    Changes: Database references
  • Version 1.2: 2021-07-14
    Changes: Database references
  • Version 1.3: 2023-10-18
    Changes: Data collection, Database references, Refinement description