2XXS | pdb_00002xxs

Solution structure of the N-terminal domain of the Shigella type III secretion protein MxiG

• PDB DOI: https://doi.org/10.2210/pdb2XXS/pdb

• Classification: PROTEIN BINDING
• Organism(s): Shigella flexneri
• Expression System: Escherichia coli BL21(DE3)
• Mutation(s): No 


• Deposited: 2010-11-11 Released: 2011-07-06 
• Deposition Author(s): McDowell, M.A., Johnson, S., Deane, J.E., McDonnell, J.M., Lea, S.M.

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Experimental Data Snapshot

• Method: SOLUTION NMR
• Conformers Calculated: 350 
• Conformers Submitted: 20 
• Selection Criteria: LOWEST TARGET FUNCTION 

Literature

Structural and Functional Studies on the N-Terminal Domain of the Shigella Type III Secretion Protein Mxig.

Mcdowell, M.A., Johnson, S., Deane, J.E., Cheung, M., Roehrich, A.D., Blocker, A.J., Mcdonnell, J.M., Lea, S.M.

(2011) J Biological Chem 286: 30606

• PubMed: 21733840 
• DOI: https://doi.org/10.1074/jbc.M111.243865
• Primary Citation Related Structures: 
  2XXS


• PubMed Abstract: 
  

  MxiG is a single-pass membrane protein that oligomerizes within the inner membrane ring of the Shigella flexneri type III secretion system (T3SS). The MxiG N-terminal domain (MxiG-N) is the predominant cytoplasmic structure; however, its role in T3SS assembly and secretion is largely uncharacterized. We have determined the solution structure of MxiG-N residues 6-112 (MxiG-N(6-112)), representing the first published structure of this T3SS domain. The structure shows strong structural homology to forkhead-associated (FHA) domains. Canonically, these cell-signaling modules bind phosphothreonine (Thr(P)) via highly conserved residues. However, the putative phosphate-binding pocket of MxiG-N(6-112) does not align with other FHA domain structures or interact with Thr(P). Furthermore, mutagenesis of potential phosphate-binding residues has no effect on S. flexneri T3SS assembly and function. Therefore, MxiG-N has a novel function for an FHA domain. Positioning of MxiG-N(6-112) within the EM density of the S. flexneri needle complex gives insight into the ambiguous stoichiometry of the T3SS, supporting models with 24 MxiG subunits in the inner membrane ring.

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Organizational Affiliation: 
• Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, United Kingdom.
Schools of Cellular and Molecular Medicine and Biochemistry, Medical Sciences Building, University of Bristol, University Walk, Bristol BS8 1TD, United Kingdom.
Department of Biochemistry, University of Oxford, Oxford OX1 3QU, United Kingdom.
Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, United Kingdom. Electronic address: [e-mail].

Biological Assembly 1  

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

Biological assembly 1 assigned by authors.

Macromolecule Content 

• Total Structure Weight: 12.18 kDa 
• Atom Count: 858 
• Modeled Residue Count: 107 
• Deposited Residue Count: 107 
• Unique protein chains: 1

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
PROTEIN MXIG	A	107	Shigella flexneri	Mutation(s): 0
UniProt
Find proteins for P0A221 (Shigella flexneri) Explore P0A221  Go to UniProtKB:  P0A221

Experimental Data & Validation

Experimental Data

• Method: SOLUTION NMR
• Conformers Calculated: 350 
• Conformers Submitted: 20 
• Selection Criteria: LOWEST TARGET FUNCTION 

Structure Validation

Entry History 

Deposition Data

• Released Date: 2011-07-06 
Deposition Author(s): McDowell, M.A., Johnson, S., Deane, J.E., McDonnell, J.M., Lea, S.M.

Revision History  

• Version 1.0: 2011-07-06
  Type: Initial release
  
• Version 1.1: 2011-09-07
  Changes: Database references, Version format compliance
• Version 2.0: 2024-05-15
  Changes: Atomic model, Data collection, Database references, Other