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

Ioannis Manolaridis, Scott M. Jackson, Nicholas M. I. Taylor, Julia Kowal, Henning Stahlberg () and Kaspar P. Locher ()
Additional contact information
Ioannis Manolaridis: Institute of Molecular Biology and Biophysics, Department of Biology
Scott M. Jackson: Institute of Molecular Biology and Biophysics, Department of Biology
Nicholas M. I. Taylor: University of Basel
Julia Kowal: Institute of Molecular Biology and Biophysics, Department of Biology
Henning Stahlberg: University of Basel
Kaspar P. Locher: Institute of Molecular Biology and Biophysics, Department of Biology

Nature, 2018, vol. 563, issue 7731, 426-430

Abstract: 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 barriers1–4. Powered by ATP, it translocates endogenous substrates, affects the pharmacokinetics of many drugs and protects against a wide array of xenobiotics, including anti-cancer drugs5–12. Previous studies have revealed the architecture of ABCG2 and the structural basis of its inhibition by small molecules and antibodies13,14. 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 (ABCG2EQ), 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 (E1S) is bound in a central, hydrophobic and cytoplasm-facing cavity about halfway across the membrane. Only one molecule of E1S 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 E1S and other substrates, and suggest that the size and binding affinity of compounds are important for distinguishing substrates from inhibitors.

Keywords: Human ABCG2; Substrate-bound State; Substrate-binding Cavity; Nucleotide-binding Domain (NBD); External Cavity (search for similar items in EconPapers)
Date: 2018
References: Add references at CitEc
Citations: View citations in EconPapers (6)

Downloads: (external link)
https://www.nature.com/articles/s41586-018-0680-3 Abstract (text/html)
Access to the full text of the articles in this series is restricted.

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:nat:nature:v:563:y:2018:i:7731:d:10.1038_s41586-018-0680-3

Ordering information: This journal article can be ordered from
https://www.nature.com/

DOI: 10.1038/s41586-018-0680-3

Access Statistics for this article

Nature is currently edited by Magdalena Skipper

More articles in Nature from Nature
Bibliographic data for series maintained by Sonal Shukla () and Springer Nature Abstracting and Indexing ().