9CTF image
Entry Detail
PDB ID:
9CTF
EMDB ID:
Title:
SapNP Reconstituted Human ABCB1 bound to Taxol in presence of ATP
Biological Source:
Source Organism:
Host Organism:
PDB Version:
Deposition Date:
2024-07-25
Release Date:
2025-01-22
Method Details:
Experimental Method:
Resolution:
3.90 Å
Aggregation State:
PARTICLE
Reconstruction Method:
SINGLE PARTICLE
Macromolecular Entities
Polymer Type:polypeptide(L)
Description:ATP-dependent translocase ABCB1
Chain IDs:A
Chain Length:1280
Number of Molecules:1
Biological Source:Homo sapiens
Primary Citation
Structural insights into binding-site access and ligand recognition by human ABCB1.
Embo J. 44 991 1006 (2025)
PMID: 39806099 DOI: 10.1038/s44318-025-00361-z

Abstact

ABCB1 is a broad-spectrum efflux pump central to cellular drug handling and multidrug resistance in humans. However, how it is able to recognize and transport a wide range of diverse substrates remains poorly understood. Here we present cryo-EM structures of lipid-embedded human ABCB1 in conformationally distinct apo-, substrate-bound, inhibitor-bound, and nucleotide-trapped states at 3.4-3.9 Å resolution, in the absence of stabilizing antibodies or mutations. The substrate-binding site is located within one half of the molecule and, in the apo state, is obstructed by the transmembrane helix (TM) 4. Substrate and inhibitor binding are distinguished by major TM rearrangements and their ligand binding chemistry, with TM4 playing a central role in all conformational transitions. Furthermore, our data identify secondary structure-breaking residues that impart localized TM flexibility and asymmetry between the two transmembrane domains. The resulting structural changes and lipid interactions that are induced by substrate and inhibitor binding can predict substrate-binding profiles and may direct ABCB1 inhibitor design.

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