7CH6

Cryo-EM structure of E.coli MlaFEB with AMPPNP


Experimental Data Snapshot

  • Method: ELECTRON MICROSCOPY
  • Resolution: 3.40 Å
  • Aggregation State: PARTICLE 
  • Reconstruction Method: SINGLE PARTICLE 

wwPDB Validation   3D Report Full Report


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Literature

Structural Insight into Phospholipid Transport by the MlaFEBD Complex from P. aeruginosa.

Zhou, C.Shi, H.Zhang, M.Zhou, L.Xiao, L.Feng, S.Im, W.Zhou, M.Zhang, X.Huang, Y.

(2021) J Mol Biol 433: 166986-166986

  • DOI: https://doi.org/10.1016/j.jmb.2021.166986
  • Primary Citation of Related Structures:  
    7CH6, 7CH7, 7CH8, 7CH9, 7CHA

  • PubMed Abstract: 

    The outer membrane (OM) of Gram-negative bacteria, which consists of lipopolysaccharides (LPS) in the outer leaflet and phospholipids (PLs) in the inner leaflet, plays a key role in antibiotic resistance and pathogen virulence. The maintenance of lipid asymmetry (Mla) pathway is known to be involved in PL transport and contributes to the lipid homeostasis of the OM, yet the underlying molecular mechanism and the directionality of PL transport in this pathway remain elusive. Here, we reported the cryo-EM structures of the ATP-binding cassette (ABC) transporter MlaFEBD from P. areuginosa, the core complex in the Mla pathway, in nucleotide-free (apo)-, ADP (ATP + vanadate)- and ATP (AMPPNP)-bound states as well as the structures of MlaFEB from E. coli in apo- and AMPPNP-bound states at a resolution range of 3.4-3.9 Å. The structures show that the MlaFEBD complex contains a total of twelve protein molecules with a stoichiometry of MlaF 2 E 2 B 2 D 6 , and binds a plethora of PLs at different locations. In contrast to canonical ABC transporters, nucleotide binding fails to trigger significant conformational changes of both MlaFEBD and MlaFEB in the nucleotide-binding and transmembrane domains of the ABC transporter, correlated with their low ATPase activities exhibited in both detergent micelles and lipid nanodiscs. Intriguingly, PLs or detergents appeared to relocate to the membrane-proximal end from the distal end of the hydrophobic tunnel formed by the MlaD hexamer in MlaFEBD upon addition of ATP, indicating that retrograde PL transport might occur in the tunnel in an ATP-dependent manner. Site-specific photocrosslinking experiment confirms that the substrate-binding pocket in the dimeric MlaE and the MlaD hexamer are able to bind PLs in vitro, in line with the notion that MlaFEBD complex functions as a PL transporter.


  • Organizational Affiliation

    National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Chaoyang District, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing100101, China.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Lipid asymmetry maintenance ABC transporter permease subunit MlaE
A, B
260Escherichia coli K-12Mutation(s): 0 
Gene Names: mlaEFAZ83_04790
Membrane Entity: Yes 
UniProt
Find proteins for P64606 (Escherichia coli (strain K12))
Explore P64606 
Go to UniProtKB:  P64606
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP64606
Sequence Annotations
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  • Reference Sequence
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Entity ID: 2
MoleculeChains Sequence LengthOrganismDetailsImage
Phospholipid ABC transporter ATP-binding protein MlaF
C, D
269Escherichia coli K-12Mutation(s): 0 
Gene Names: mlaFFAZ83_04795
EC: 7.6.2
Membrane Entity: Yes 
UniProt
Find proteins for P63386 (Escherichia coli (strain K12))
Explore P63386 
Go to UniProtKB:  P63386
Entity Groups  
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UniProt GroupP63386
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  • Reference Sequence
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 3
MoleculeChains Sequence LengthOrganismDetailsImage
Lipid asymmetry maintenance protein MlaB
E, F
97Escherichia coli K-12Mutation(s): 0 
Gene Names: mlaBFAZ83_04775
UniProt
Find proteins for P64602 (Escherichia coli (strain K12))
Explore P64602 
Go to UniProtKB:  P64602
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP64602
Sequence Annotations
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: ELECTRON MICROSCOPY
  • Resolution: 3.40 Å
  • Aggregation State: PARTICLE 
  • Reconstruction Method: SINGLE PARTICLE 
EM Software:
TaskSoftware PackageVersion
RECONSTRUCTIONRELION3.0

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2021-08-04
    Type: Initial release
  • Version 1.1: 2024-03-27
    Changes: Data collection, Database references