Biological Assembly 1  

 3D View: Structure | Electron Density

Global Symmetry: Dihedral - D6  (3D View)
Global Stoichiometry: Homo 12-mer - A12 

Biological assembly 1 generated by PISA (software)

Biological Assembly 2  

 3D View: Structure | Electron Density

Global Symmetry: Cyclic - C6  (3D View)
Global Stoichiometry: Homo 6-mer - A6 

Biological assembly 2 assigned by authors and generated by PISA (software)

Macromolecule Content

• Total Structure Weight: 39.87 kDa 
• Atom Count: 2486 
• Modelled Residue Count: 324 
• Deposited Residue Count: 369 
• Unique protein chains: 1

4DK0

Crystal structure of MacA from Actinobacillus actinomycetemcomitans

• DOI: 10.2210/pdb4DK0/pdb

• Classification: MEMBRANE PROTEIN
• Organism(s): Aggregatibacter actinomycetemcomitans
• Expression System: Escherichia coli
• Mutation(s): No 


• Deposited: 2012-02-03 Released: 2012-03-07 
• Deposition Author(s): Xu, Y., Piao, S., Ha, N.C.

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Experimental Data Snapshot

• Method: X-RAY DIFFRACTION
• Resolution: 3.50 Å
• R-Value Free: 0.390 
• R-Value Work: 0.338 
• R-Value Observed: 0.344 

Literature

Assembly and channel opening of outer membrane protein in tripartite drug efflux pumps of Gram-negative bacteria.

Xu, Y., Moeller, A., Jun, S.Y., Le, M., Yoon, B.Y., Kim, J.S., Lee, K., Ha, N.C.

(2012) J Biol Chem 287: 11740-11750

• PubMed: 22308040 
• DOI: 10.1074/jbc.M111.329375
• Primary Citation of Related Structures:  
  4DK0, 4DK1


• PubMed Abstract: 
  

Gram-negative bacteria are capable of expelling diverse xenobiotic substances from within the cell by use of three-component efflux pumps in which the energy-activated inner membrane transporter is connected to the outer membrane channel protein via the membrane fusion protein. In this work, we describe the crystal structure of the membrane fusion protein MexA from the Pseudomonas aeruginosa MexAB-OprM pump in the hexameric ring arrangement. Electron microscopy study on the chimeric complex of MexA and the outer membrane protein OprM reveals that MexA makes a tip-to-tip interaction with OprM, which suggests a docking model for MexA and OprM. This docking model agrees well with genetic results and depicts detailed interactions. Opening of the OprM channel is accompanied by the simultaneous exposure of a protein structure resembling a six-bladed cogwheel, which intermeshes with the complementary cogwheel structure in the MexA hexamer. Taken together, we suggest an assembly and channel opening model for the MexAB-OprM pump. This study provides a better understanding of multidrug resistance in Gram-negative bacteria.

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Organizational Affiliation: 

Department of Manufacturing Pharmacy, College of Pharmacy and Research Institute for Drug Development, Pusan National University, Busan 609-735, Korea.

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
Putative MacA	A	369	Aggregatibacter actinomycetemcomitans	Mutation(s): 0  Gene Names: macA
Find proteins for Q2EHL9 (Aggregatibacter actinomycetemcomitans) Explore Q2EHL9  Go to UniProtKB:  Q2EHL9

Small Molecules

Modified Residues  1 Unique
ID	Chains	Type	Formula	2D Diagram	Parent
MSE	A	L-PEPTIDE LINKING	C5 H11 N O2 Se		MET

Experimental Data & Validation

Experimental Data

• Method: X-RAY DIFFRACTION
• Resolution: 3.50 Å
• R-Value Free: 0.390 
• R-Value Work: 0.338 
• R-Value Observed: 0.344 
• Space Group: P 6 2 2

Unit Cell:

Length ( Å )	Angle ( ˚ )
a = 109.188	α = 90
b = 109.188	β = 90
c = 255.442	γ = 120

Software Package:

Software Name	Purpose
HKL-2000	data collection
SOLVE	phasing
PHENIX	refinement
HKL-2000	data reduction
HKL-2000	data scaling

Structure Validation

Entry History 

Deposition Data

• Deposited Date: 2012-02-03 
• Released Date: 2012-03-07 
Deposition Author(s): Xu, Y., Piao, S., Ha, N.C.

Revision History  

• Version 1.0: 2012-03-07
  Type: Initial release
  
• Version 1.1: 2015-12-09
  Changes: Database references