Biological Assembly 1  

 3D View: Structure | Electron Density

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

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

Macromolecule Content

• Total Structure Weight: 74.37 kDa 
• Atom Count: 4097 
• Residue Count: 533 
• Unique protein chains: 1

3FPP

Crystal structure of E.coli MacA

• DOI: 10.2210/pdb3FPP/pdb

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


• Deposited: 2009-01-06 Released: 2009-04-28 
• Deposition Author(s): Yum, S., Xu, Y., Piao, S., Ha, N.-C.

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Experimental Data Snapshot

• Method: X-RAY DIFFRACTION
• Resolution: 2.99 Å
• R-Value Free: 0.349 
• R-Value Work: 0.283 
• R-Value Observed: 0.283 

Literature

Crystal structure of the periplasmic component of a tripartite macrolide-specific efflux pump

Yum, S., Xu, Y., Piao, S., Sim, S.-H., Kim, H.-M., Jo, W.-S., Kim, K.-J., Kweon, H.-S., Jeong, M.-H., Jeon, H., Lee, K., Ha, N.-C.

(2009) J Mol Biol 387: 1286-1297

• PubMed: 19254725 
• DOI: 10.1016/j.jmb.2009.02.048
• Primary Citation of Related Structures:  
  3FPP


• PubMed Abstract: 
  

In Gram-negative bacteria, type I protein secretion systems and tripartite drug efflux pumps have a periplasmic membrane fusion protein (MFP) as an essential component. MFPs bridge the outer membrane factor and an inner membrane transporter, although the oligomeric state of MFPs remains unclear. The most characterized MFP AcrA connects the outer membrane factor TolC and the resistance-nodulation-division-type efflux transporter AcrB, which is a major multidrug efflux pump in Escherichia coli. MacA is the periplasmic MFP in the MacAB-TolC pump, where MacB was characterized as a macrolide-specific ATP-binding-cassette-type efflux transporter. Here, we report the crystal structure of E. coli MacA and the experimentally phased map of Actinobacillus actinomycetemcomitans MacA, which reveal a domain orientation of MacA different from that of AcrA. Notably, a hexameric assembly of MacA was found in both crystals, exhibiting a funnel-like structure with a central channel and a conical mouth. The hexameric MacA assembly was further confirmed by electron microscopy and functional studies in vitro and in vivo. The hexameric structure of MacA provides insight into the oligomeric state in the functional complex of the drug efflux pump and type I secretion system.

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Organizational Affiliation: 

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
Macrolide-specific efflux protein macA	A, B	341	Escherichia coli	Mutation(s): 0  Gene Names: macA
Find proteins for P75830 (Escherichia coli (strain K12)) Explore P75830  Go to UniProtKB:  P75830

Experimental Data & Validation

Experimental Data

• Method: X-RAY DIFFRACTION
• Resolution: 2.99 Å
• R-Value Free: 0.349 
• R-Value Work: 0.283 
• R-Value Observed: 0.283 
• Space Group: P 3 2 1

Unit Cell:

Length ( Å )	Angle ( ˚ )
a = 128.517	α = 90
b = 128.517	β = 90
c = 110.311	γ = 120

Software Package:

Software Name	Purpose
HKL-2000	data collection
MOLREP	phasing
CNS	refinement
HKL-2000	data reduction
HKL-2000	data scaling

Structure Validation

Entry History 

Deposition Data

• Deposited Date: 2009-01-06 
• Released Date: 2009-04-28 
Deposition Author(s): Yum, S., Xu, Y., Piao, S., Ha, N.-C.

Revision History 

• Version 1.0: 2009-04-28
  Type: Initial release
  
• Version 1.1: 2011-07-13
  Changes: Version format compliance