3B5W

Crystal Structure of Eschericia coli MsbA

Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 5.30 Å
  • R-Value Free: 0.311 
  • R-Value Work: 0.276 

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Literature

Flexibility in the ABC transporter MsbA: Alternating access with a twist.

Ward, A., Reyes, C.L., Yu, J., Roth, C.B., Chang, G.

(2007) Proc Natl Acad Sci U S A 104: 19005-19010

  • DOI: 10.1073/pnas.0709388104
  • Primary Citation of Related Structures:  
    3B5W, 3B5X, 3B5Y, 3B5Z, 3B60

  • PubMed Abstract: 

    • ATP-binding cassette (ABC) transporters are integral membrane proteins that translocate a wide variety of substrates across cellular membranes and are conserved from bacteria to humans. Here we compare four x-ray structures of the bacterial ABC lipid flippase, MsbA, trapped in different conformations, two nucleotide-bound structures and two in the absence of nucleotide ...

    ATP-binding cassette (ABC) transporters are integral membrane proteins that translocate a wide variety of substrates across cellular membranes and are conserved from bacteria to humans. Here we compare four x-ray structures of the bacterial ABC lipid flippase, MsbA, trapped in different conformations, two nucleotide-bound structures and two in the absence of nucleotide. Comparison of the nucleotide-free conformations of MsbA reveals a flexible hinge formed by extracellular loops 2 and 3. This hinge allows the nucleotide-binding domains to disassociate while the ATP-binding half sites remain facing each other. The binding of the nucleotide causes a packing rearrangement of the transmembrane helices and changes the accessibility of the transporter from cytoplasmic (inward) facing to extracellular (outward) facing. The inward and outward openings are mediated by two different sets of transmembrane helix interactions. Altogether, the conformational changes between these structures suggest that large ranges of motion may be required for substrate transport.

    Organizational Affiliation: 

    Departments of Cell Biology and Molecular Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, CB-105, La Jolla, CA 92037, USA.



Macromolecules
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(by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
Lipid A export ATP-binding/permease protein msbA
A, B, C, D, E, F, G, H
A, B, C, D, E, F, G, H
582Escherichia coliMutation(s): 0 
Gene Names: msbA
EC: 3.6.3 (PDB Primary Data), 7.5.2.6 (UniProt)
Membrane Entity: Yes 
UniProt
Find proteins for P60752 (Escherichia coli (strain K12))
Explore P60752 
Go to UniProtKB:  P60752
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP60752
Protein Feature View
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 5.30 Å
  • R-Value Free: 0.311 
  • R-Value Work: 0.276 
  • Space Group: P 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 107.79α = 83.47
b = 126.07β = 76.25
c = 206.56γ = 84.07
Software Package:
Software NamePurpose
CNSrefinement
PDB_EXTRACTdata extraction
HKL-2000data reduction
HKL-2000data scaling
PHASESphasing

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2007-12-04
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Version format compliance