Crystal structure of the periplasmic region of MacB from Actinobacillus actinomycetemcomitans

Experimental Data Snapshot

  • Resolution: 2.00 Å
  • R-Value Free: 0.250 
  • R-Value Work: 0.200 
  • R-Value Observed: 0.202 

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Crystal structure of the periplasmic region of MacB, a noncanonic ABC transporter

Xu, Y.Sim, S.-H.Nam, K.H.Jin, X.L.Kim, H.-M.Hwang, K.Y.Lee, K.Ha, N.-C.

(2009) Biochemistry 48: 5218-5225

  • DOI: https://doi.org/10.1021/bi900415t
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    MacB is a noncanonic ABC-type transporter within Gram-negative bacteria, which is responsible both for the efflux of macrolide antibiotics and for the secretion of heat-stable enterotoxin II. In Escherichia coli, MacB requires the membrane fusion protein MacA and the multifunctional outer membrane channel TolC to pump substrates to the external medium. Sequence analysis of MacB suggested that MacB has a relatively large periplasmic region. To gain insight into how MacB assembles with MacA and TolC, we determined the crystal structure of the periplasmic region of Actinobacillus actinomycetemcomitans MacB. Fold matching program reveals that parts of the MacB periplasmic region have structural motifs in common with the RND-type transporter AcrB. Since it behaved as a monomer in solution, our finding is consistent with the dimeric nature of full-length MacB, providing an insight into the assembly in the tripartite efflux pump.

  • Organizational Affiliation

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

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Macrolide export ATP-binding/permease protein macB226Aggregatibacter actinomycetemcomitansMutation(s): 0 
Gene Names: macBMACB_ACTAC
EC: 3.6.3
Find proteins for Q2EHL8 (Aggregatibacter actinomycetemcomitans)
Explore Q2EHL8 
Go to UniProtKB:  Q2EHL8
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ2EHL8
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 2.00 Å
  • R-Value Free: 0.250 
  • R-Value Work: 0.200 
  • R-Value Observed: 0.202 
  • Space Group: H 3 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 108.444α = 90
b = 108.444β = 90
c = 92.892γ = 120
Software Package:
Software NamePurpose
ADSCdata collection
HKL-2000data reduction
HKL-2000data scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2009-05-26
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Version format compliance