Cryo-EM structure of the ABCG2 E211Q mutant bound to ATP and Magnesium (alternative placement of Magnesium into the cryo-EM density)

Experimental Data Snapshot

  • Resolution: 3.09 Å
  • Aggregation State: PARTICLE 
  • Reconstruction Method: SINGLE PARTICLE 

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Cryo-EM structures of a human ABCG2 mutant trapped in ATP-bound and substrate-bound states.

Manolaridis, I.Jackson, S.M.Taylor, N.M.I.Kowal, J.Stahlberg, H.Locher, K.P.

(2018) Nature 563: 426-430

  • DOI: https://doi.org/10.1038/s41586-018-0680-3
  • Primary Citation of Related Structures:  
    6HBU, 6HCO, 6HZM

  • PubMed Abstract: 

    ABCG2 is a transporter protein of the ATP-binding-cassette (ABC) family that is expressed in the plasma membrane in cells of various tissues and tissue barriers, including the blood-brain, blood-testis and maternal-fetal barriers 1-4 . Powered by ATP, it translocates endogenous substrates, affects the pharmacokinetics of many drugs and protects against a wide array of xenobiotics, including anti-cancer drugs 5-12 . Previous studies have revealed the architecture of ABCG2 and the structural basis of its inhibition by small molecules and antibodies 13,14 . However, the mechanisms of substrate recognition and ATP-driven transport are unknown. Here we present high-resolution cryo-electron microscopy (cryo-EM) structures of human ABCG2 in a substrate-bound pre-translocation state and an ATP-bound post-translocation state. For both structures, we used a mutant containing a glutamine replacing the catalytic glutamate (ABCG2 EQ ), which resulted in reduced ATPase and transport rates and facilitated conformational trapping for structural studies. In the substrate-bound state, a single molecule of estrone-3-sulfate (E 1 S) is bound in a central, hydrophobic and cytoplasm-facing cavity about halfway across the membrane. Only one molecule of E 1 S can bind in the observed binding mode. In the ATP-bound state, the substrate-binding cavity has collapsed while an external cavity has opened to the extracellular side of the membrane. The ATP-induced conformational changes include rigid-body shifts of the transmembrane domains, pivoting of the nucleotide-binding domains (NBDs), and a change in the relative orientation of the NBD subdomains. Mutagenesis and in vitro characterization of transport and ATPase activities demonstrate the roles of specific residues in substrate recognition, including a leucine residue that forms a 'plug' between the two cavities. Our results show how ABCG2 harnesses the energy of ATP binding to extrude E 1 S and other substrates, and suggest that the size and binding affinity of compounds are important for distinguishing substrates from inhibitors.

  • Organizational Affiliation

    Institute of Molecular Biology and Biophysics, Department of Biology, ETH Zurich, Switzerland.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
ATP-binding cassette sub-family G member 2
A, B
655Homo sapiensMutation(s): 1 
Membrane Entity: Yes 
UniProt & NIH Common Fund Data Resources
Find proteins for Q9UNQ0 (Homo sapiens)
Explore Q9UNQ0 
Go to UniProtKB:  Q9UNQ0
GTEx:  ENSG00000118777 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ9UNQ0
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 3.09 Å
  • Aggregation State: PARTICLE 
  • Reconstruction Method: SINGLE PARTICLE 
EM Software:
TaskSoftware PackageVersion

Structure Validation

View Full Validation Report

Entry History & Funding Information

Deposition Data

Funding OrganizationLocationGrant Number
Swiss National Science FoundationSwitzerlandETH-22-14-1

Revision History  (Full details and data files)

  • Version 1.0: 2018-11-14
    Type: Initial release
  • Version 1.1: 2018-11-21
    Changes: Data collection, Database references
  • Version 1.2: 2018-11-28
    Changes: Data collection, Database references
  • Version 1.3: 2019-12-18
    Changes: Other