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-Structure paper
タイトル | Structural basis of substrate recognition and translocation by human ABCA4. |
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ジャーナル・号・ページ | Nat Commun, Vol. 12, Issue 1, Page 3853, Year 2021 |
掲載日 | 2021年6月22日 |
著者 | Tian Xie / Zike Zhang / Qi Fang / Bowen Du / Xin Gong / |
PubMed 要旨 | Human ATP-binding cassette (ABC) subfamily A (ABCA) transporters mediate the transport of various lipid compounds across the membrane. Mutations in human ABCA transporters have been described to ...Human ATP-binding cassette (ABC) subfamily A (ABCA) transporters mediate the transport of various lipid compounds across the membrane. Mutations in human ABCA transporters have been described to cause severe hereditary disorders associated with impaired lipid transport. However, little is known about the mechanistic details of substrate recognition and translocation by ABCA transporters. Here, we present three cryo-EM structures of human ABCA4, a retina-specific ABCA transporter, in distinct functional states at resolutions of 3.3-3.4 Å. In the nucleotide-free state, the two transmembrane domains (TMDs) exhibit a lateral-opening conformation, allowing the lateral entry of substrate from the lipid bilayer. The N-retinylidene-phosphatidylethanolamine (NRPE), the physiological lipid substrate of ABCA4, is sandwiched between the two TMDs in the luminal leaflet and is further stabilized by an extended loop from extracellular domain 1. In the ATP-bound state, the two TMDs display a closed conformation, which precludes the substrate binding. Our study provides a molecular basis to understand the mechanism of ABCA4-mediated NRPE recognition and translocation, and suggests a common 'lateral access and extrusion' mechanism for ABCA-mediated lipid transport. |
リンク | Nat Commun / PubMed:34158497 / PubMed Central |
手法 | EM (単粒子) |
解像度 | 3.3 - 3.4 Å |
構造データ | EMDB-31000, PDB-7e7i: EMDB-31001, PDB-7e7o: EMDB-31002, PDB-7e7q: |
化合物 | ChemComp-NAG: ChemComp-3PE: ChemComp-HZL: ChemComp-ATP: ChemComp-MG: |
由来 |
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キーワード | TRANSLOCASE / lipid transport / MEMBRANE PROTEIN |