Biological Assembly 1  

 3D View: Structure | Electron Density

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Global Symmetry: Cyclic - C2  (3D View)
Global Stoichiometry: Homo 2-mer - A2 

Biological assembly 1 assigned by authors.

Macromolecule Content

• Total Structure Weight: 129249.85 
• Atom Count: 1144 
• Residue Count: 1164 
• Unique protein chains: 1

3B5X

Crystal Structure of MsbA from Vibrio cholerae

• DOI: 10.2210/pdb3B5X/pdb

• Classification: MEMBRANE PROTEIN
• Organism(s): Vibrio cholerae serotype O1 (strain ATCC 39315 / El Tor Inaba N16961)
• Expression System: Escherichia coli BL21


• Deposited: 2007-10-26 Released: 2007-12-04 
• Deposition Author(s): Ward, A., Reyes, C.L., Yu, J., Roth, C.B., Chang, G.

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Experimental Data Snapshot

• Method: X-RAY DIFFRACTION
• Resolution: 5.5 Å
• R-Value Free: 0.360 
• R-Value Work: 0.348 

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.Usa 104: 19005-19010

• PubMed: 18024585 
• DOI: 10.1073/pnas.0709388104
• Primary Citation of Related Structures:  
  3B60, 3B5Z, 3B5Y, 3B5W


• 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. 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.

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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

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details
Lipid A export ATP-binding/permease protein msbA	A, B	582	Vibrio cholerae serotype O1 (strain ATCC 39315 / El Tor Inaba N16961)	Mutation(s): 0  Gene Names: msbA EC: 3.6.3.-
Membrane protein mpstruct	Group:  TRANSMEMBRANE PROTEINS: ALPHA-HELICAL		Sub Group:  ATP Binding Cassette (ABC) Transporters	Protein:  MsbA Lipid "flippase" with bound AMPPNP
Find proteins for Q9KQW9 (Vibrio cholerae serotype O1 (strain ATCC 39315 / El Tor Inaba N16961)) Go to UniProtKB:  Q9KQW9

Experimental Data & Validation

Experimental Data

• Method: X-RAY DIFFRACTION
• Resolution: 5.5 Å
• R-Value Free: 0.360 
• R-Value Work: 0.348 
• Space Group: P 2₁ 2₁ 2₁

Unit Cell:

Length (Å)	Angle (°)
a = 120.590	α = 90.00
b = 150.420	β = 90.00
c = 148.880	γ = 90.00

Software Package:

Software Name	Purpose
HKL-2000	data reduction
CNS	refinement
PDB_EXTRACT	data extraction
HKL-2000	data scaling
PHASES	phasing

Structure Validation

Entry History 

Deposition Data

• Deposited Date: 2007-10-26 
• Released Date: 2007-12-04 
• Deposition Author(s): Ward, A., Reyes, C.L., Yu, J., Roth, C.B., Chang, G.

Revision History 

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