4HUQ

Crystal Structure of a transporter


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 3.00 Å
  • R-Value Free: 0.264 
  • R-Value Work: 0.215 
  • R-Value Observed: 0.217 

wwPDB Validation   3D Report Full Report


This is version 1.3 of the entry. See complete history


Literature

Crystal structure of a folate energy-coupling factor transporter from Lactobacillus brevis.

Xu, K.Zhang, M.Zhao, Q.Yu, F.Guo, H.Wang, C.He, F.Ding, J.Zhang, P.

(2013) Nature 497: 268-271

  • DOI: https://doi.org/10.1038/nature12046
  • Primary Citation of Related Structures:  
    4HUQ

  • PubMed Abstract: 

    ATP-binding cassette (ABC) transporters, composed of importers and exporters, form one of the biggest protein superfamilies that transport a variety of substrates across the membrane, powered by ATP hydrolysis. Most ABC transporters are composed of two transmembrane domains and two cytoplasmic nucleotide-binding domains. Also, importers from prokaryotes usually have extra solute-binding proteins in the periplasm that are responsible for the binding of substrates. Structures of importers have been reported that suggested a two-state model for the transport mechanism. Energy-coupling factor (ECF) transporters belong to a new class of ATP-binding cassette importers. Each ECF transporter comprises an energy-coupling module consisting of a transmembrane T protein (EcfT), two nucleotide-binding proteins (EcfA and EcfA'), and another transmembrane substrate-specific binding S protein (EcfS). Despite the similarities with ABC transporters, ECF transporters have different organizational and functional properties. The lack of solute-binding proteins in ECF transporters differentiates them clearly from the canonical ABC importers. Previously reported structures of the EcfS proteins RibU and ThiT clearly demonstrated the binding site of substrate riboflavin and thiamine, respectively. However, the organization of the four different components and the transport mechanism of ECF transporters remain unknown. Here we present the structure of an intact folate ECF transporter from Lactobacillus brevis at a resolution of 3 Å. This structure was captured in an inward-facing, nucleotide-free conformation with no bound substrate. The folate-binding protein FolT is nearly parallel to the membrane and is bound almost entirely by EcfT, which adopts an L shape and connects to EcfA and EcfA' through two coupling helices. Two conserved XRX motifs from the coupling helices of EcfT have a vital role in energy coupling by docking into EcfA-EcfA'. We propose a transport model that involves a substantial conformational change of FolT.


  • Organizational Affiliation

    National Key Laboratory of Plant Molecular Genetics, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 300 Fenglin Road, Shanghai 200032, China.


Macromolecules
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Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Energy-coupling factor transporter ATP-binding protein EcfA 1290Levilactobacillus brevis ATCC 367Mutation(s): 0 
Gene Names: cbiO1ecfA1LVIS_1661unknown transporter
EC: 3.6.3
Membrane Entity: Yes 
UniProt
Find proteins for Q03PY6 (Levilactobacillus brevis (strain ATCC 367 / BCRC 12310 / CIP 105137 / JCM 1170 / LMG 11437 / NCIMB 947 / NCTC 947))
Explore Q03PY6 
Go to UniProtKB:  Q03PY6
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ03PY6
Sequence Annotations
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  • Reference Sequence
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Entity ID: 2
MoleculeChains Sequence LengthOrganismDetailsImage
Energy-coupling factor transporter ATP-binding protein EcfA 2279Levilactobacillus brevis ATCC 367Mutation(s): 0 
Gene Names: ecfA2cbiO2LVIS_1662
EC: 3.6.3 (PDB Primary Data), 7 (UniProt)
Membrane Entity: Yes 
UniProt
Find proteins for Q03PY5 (Levilactobacillus brevis (strain ATCC 367 / BCRC 12310 / CIP 105137 / JCM 1170 / LMG 11437 / NCIMB 947 / NCTC 947))
Explore Q03PY5 
Go to UniProtKB:  Q03PY5
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UniProt GroupQ03PY5
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  • Reference Sequence
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Entity ID: 3
MoleculeChains Sequence LengthOrganismDetailsImage
Uncharacterized proteinC [auth S]174Levilactobacillus brevis ATCC 367Mutation(s): 0 
Gene Names: LVIS_0823
Membrane Entity: Yes 
UniProt
Find proteins for Q03S56 (Levilactobacillus brevis (strain ATCC 367 / BCRC 12310 / CIP 105137 / JCM 1170 / LMG 11437 / NCIMB 947 / NCTC 947))
Explore Q03S56 
Go to UniProtKB:  Q03S56
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UniProt GroupQ03S56
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  • Reference Sequence
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Entity ID: 4
MoleculeChains Sequence LengthOrganismDetailsImage
Energy-coupling factor transporter transmembrane protein EcfTD [auth T]280Levilactobacillus brevis ATCC 367Mutation(s): 0 
Gene Names: ecfTLVIS_1660
Membrane Entity: Yes 
UniProt
Find proteins for Q03PY7 (Levilactobacillus brevis (strain ATCC 367 / BCRC 12310 / CIP 105137 / JCM 1170 / LMG 11437 / NCIMB 947 / NCTC 947))
Explore Q03PY7 
Go to UniProtKB:  Q03PY7
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ03PY7
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 3.00 Å
  • R-Value Free: 0.264 
  • R-Value Work: 0.215 
  • R-Value Observed: 0.217 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 80.608α = 90
b = 149.004β = 90
c = 170.855γ = 90
Software Package:
Software NamePurpose
PHENIXrefinement
PDB_EXTRACTdata extraction
HKL-2000data collection
HKL-2000data reduction
HKL-2000data scaling
SHELXSphasing

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2013-04-17
    Type: Initial release
  • Version 1.1: 2013-05-01
    Changes: Database references
  • Version 1.2: 2013-05-22
    Changes: Database references
  • Version 1.3: 2024-02-28
    Changes: Data collection, Database references