29JD | pdb_000029jd

NMR Structure of the Calcium bound form of OutG, major pilin from Dickeya dadantii T2SS

• PDB DOI: https://doi.org/10.2210/pdb29JD/pdb
• BMRB: 51296

• Classification: PROTEIN TRANSPORT
• Organism(s): Dickeya dadantii
• Expression System: Escherichia coli BL21(DE3)
• Mutation(s): No 


• Deposited: 2026-03-16 Released: 2026-09-09 
• Deposition Author(s): Bardiaux, B., Jacobsen, T., Dazzoni, R., Nilges, M., Francetic, O., Shevchik, V., Izadi-Pruneyre, N.
• Funding Organization(s): H2020 Marie Curie Actions of the European Commission, Agence Nationale de la Recherche (ANR)

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Experimental Data Snapshot

• Method: SOLUTION NMR
• Conformers Calculated: 50 
• Conformers Submitted: 10 
• Selection Criteria: structures with the lowest energy 

Literature

Structural determinants of endopilus assembly, stability, and functional specificity in bacterial type II secretion.

Lejeune, M., Ivashchenko, S., Dazzoni, R., Bardiaux, B., Sonani, R.R., Vos, M., Jacobsen, T., Egelman, E.H., Nilges, M., Francetic, O., Shevchik, V.E., Izadi-Pruneyre, N.

(2026) Structure 

• PubMed: 42624105 
• DOI: https://doi.org/10.1016/j.str.2026.07.013
• Primary Citation Related Structures: 
  29JD


• PubMed Abstract: 
  

  Gram-negative bacteria employ the type II secretion system (T2SS) to transport folded protein effectors via a periplasmic helical polymer called the endopilus, composed of one major and four minor pilin subunits. Endopili resemble type IV pili but feature a conserved calcium-binding site stabilizing their major pilins. Endopilus polymerization is coupled to substrate translocation through a dedicated outer membrane channel. We compared T2SSs from plant and human pathogens, Dickeya dadantii and Klebsiella oxytoca, respectively. Despite different ecological niches and secreted effectors, their major pilins (OutG and PulG) share >77% sequence identity. Using NMR and cryo-EM, we solved structures of calcium-bound OutG monomer, as well as OutG and PulG endopili at 3.6 Å resolution. Combining structural, mutational, and biophysical analyses with in vivo assays, we identified key determinants of secretion specificity and endopilus stability. Our findings reveal how minor sequence variations in conserved nanomachines drive functional adaptation to diverse environments.

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Organizational Affiliation: 
• Institut Pasteur, Université Paris Cité, CNRS UMR3528, Bacterial Transmembrane Systems Unit, 75015 Paris, France.
Institut Pasteur, Université Paris Cité, CNRS UMR3528, Structural Bioinformatics Unit, 75015 Paris, France.
Department of Biochemistry and Molecular Genetics, University of Virginia Medical School, Charlottesville, VA, USA.
Institut Pasteur, Université Paris Cité, Nanoimaging Core Facility, 75015 Paris, France.
Institut Pasteur, Université Paris Cité, CNRS UMR3528, Biochemistry of Macromolecular Interactions Unit, 75015 Paris, France. Electronic address: [e-mail].
Université Lyon 1, INSA Lyon, CNRS UMR 5240 Microbiologie Adaptation et Pathogénie, Villeurbanne, France. Electronic address: [e-mail].
Institut Pasteur, Université Paris Cité, CNRS UMR3528, Bacterial Transmembrane Systems Unit, 75015 Paris, France. Electronic address: [e-mail].

Biological Assembly 1  

Global Symmetry: Asymmetric - C1 
Global Stoichiometry: Monomer - A1 

Biological assembly 1 assigned by authors and generated by (software)

Biological Assembly Evidence: native gel electrophoresis

Macromolecule Content 

• Total Structure Weight: 13.59 kDa 
• Atom Count: 953 
• Modeled Residue Count: 125 
• Deposited Residue Count: 125 
• Unique protein chains: 1

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
Type II secretion system core protein G	A	125	Dickeya dadantii	Mutation(s): 0  Gene Names: outG, Dda3937_02418
UniProt
Find proteins for E0SM38 (Dickeya dadantii (strain 3937)) Explore E0SM38  Go to UniProtKB:  E0SM38

Small Molecules

Ligands 1 Unique
ID	Chains	Name / Formula / InChI Key	2D Diagram
CA (Subject of Investigation/LOI)	B [auth A]	CALCIUM ION Ca BHPQYMZQTOCNFJ-UHFFFAOYSA-N

Experimental Data & Validation

Experimental Data

• Method: SOLUTION NMR
• Conformers Calculated: 50 
• Conformers Submitted: 10 
• Selection Criteria: structures with the lowest energy 

Structure Validation

Entry History 

& Funding Information

Deposition Data

• Released Date: 2026-09-09 
Deposition Author(s): Bardiaux, B., Jacobsen, T., Dazzoni, R., Nilges, M., Francetic, O., Shevchik, V., Izadi-Pruneyre, N.

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Funding Organization	Location	Grant Number
H2020 Marie Curie Actions of the European Commission	European Union	765042
Agence Nationale de la Recherche (ANR)	France	ANR-19-CE11-0020-01

Revision History  

• Version 1.0: 2026-09-09
  Type: Initial release