| Autor: |
Jing Xue, Tian Xie, Weizhong Zeng, Youxing Jiang, Xiao-chen Bai |
| Jazyk: |
angličtina |
| Rok vydání: |
2020 |
| Předmět: |
|
| Zdroj: |
eLife, Vol 9 (2020) |
| Druh dokumentu: |
article |
| ISSN: |
2050-084X |
| DOI: |
10.7554/eLife.58823 |
| Popis: |
ZnT8 is a Zn2+/H+ antiporter that belongs to SLC30 family and plays an essential role in regulating Zn2+ accumulation in the insulin secretory granules of pancreatic β cells. However, the Zn2+/H+ exchange mechanism of ZnT8 remains unclear due to the lack of high-resolution structures. Here, we report the cryo-EM structures of human ZnT8 (HsZnT8) in both outward- and inward-facing conformations. HsZnT8 forms a dimeric structure with four Zn2+ binding sites within each subunit: a highly conserved primary site in transmembrane domain (TMD) housing the Zn2+ substrate; an interfacial site between TMD and C-terminal domain (CTD) that modulates the Zn2+ transport activity of HsZnT8; and two adjacent sites buried in the cytosolic domain and chelated by conserved residues from CTD and the His-Cys-His (HCH) motif from the N-terminal segment of the neighboring subunit. A comparison of the outward- and inward-facing structures reveals that the TMD of each HsZnT8 subunit undergoes a large structural rearrangement, allowing for alternating access to the primary Zn2+ site during the transport cycle. Collectively, our studies provide the structural insights into the Zn2+/H+ exchange mechanism of HsZnT8. |
| Databáze: |
Directory of Open Access Journals |
| Externí odkaz: |
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