7M1Q image
Entry Detail
PDB ID:
7M1Q
EMDB ID:
Title:
Human ABCA4 structure in complex with N-ret-PE
Biological Source:
Source Organism:
Host Organism:
PDB Version:
Deposition Date:
2021-03-14
Release Date:
2021-09-08
Method Details:
Experimental Method:
Resolution:
2.92 Å
Aggregation State:
PARTICLE
Reconstruction Method:
SINGLE PARTICLE
Macromolecular Entities
Polymer Type:polypeptide(L)
Description:Retinal-specific phospholipid-transporting ATPase ABCA4
Chain IDs:A
Chain Length:2273
Number of Molecules:1
Biological Source:Homo sapiens
Primary Citation
Cryo-EM structures of the ABCA4 importer reveal mechanisms underlying substrate binding and Stargardt disease.
Nat Commun 12 5902 5902 (2021)
PMID: 34625547 DOI: 10.1038/s41467-021-26161-7

Abstact

ABCA4 is an ATP-binding cassette (ABC) transporter that flips N-retinylidene-phosphatidylethanolamine (N-Ret-PE) from the lumen to the cytoplasmic leaflet of photoreceptor membranes. Loss-of-function mutations cause Stargardt disease (STGD1), a macular dystrophy associated with severe vision loss. To define the mechanisms underlying substrate binding and STGD1, we determine the cryo-EM structure of ABCA4 in its substrate-free and bound states. The two structures are similar and delineate an elongated protein with the two transmembrane domains (TMD) forming an outward facing conformation, extended and twisted exocytoplasmic domains (ECD), and closely opposed nucleotide binding domains. N-Ret-PE is wedged between the two TMDs and a loop from ECD1 within the lumen leaflet consistent with a lateral access mechanism and is stabilized through hydrophobic and ionic interactions with residues from the TMDs and ECDs. Our studies provide a framework for further elucidating the molecular mechanism associated with lipid transport and disease and developing promising disease interventions.

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Primary Citation of related structures