7Y5H
Cryo-EM structure of a eukaryotic ZnT8 at a low pH
Summary for 7Y5H
| Entry DOI | 10.2210/pdb7y5h/pdb |
| Related | 7Y5G |
| EMDB information | 33619 33620 |
| Descriptor | Zinc transporter 8, ZINC ION (2 entities in total) |
| Functional Keywords | zinc transporter, slc30, znt, cdf, proton-coupled antiporter, membrane protein |
| Biological source | Xenopus tropicalis (tropical clawed frog) |
| Total number of polymer chains | 2 |
| Total formula weight | 83339.70 |
| Authors | |
| Primary citation | Zhang, S.,Fu, C.,Luo, Y.,Xie, Q.,Xu, T.,Sun, Z.,Su, Z.,Zhou, X. Cryo-EM structure of a eukaryotic zinc transporter at a low pH suggests its Zn 2+ -releasing mechanism. J.Struct.Biol., 215:107926-107926, 2022 Cited by PubMed Abstract: Zinc transporter 8 (ZnT8) is mainly expressed in pancreatic islet β cells and is responsible for H-coupled uptake (antiport) of Zn into the lumen of insulin secretory granules. Structures of human ZnT8 and its prokaryotic homolog YiiP have provided structural basis for constructing a plausible transport cycle for Zn. However, the mechanistic role that protons play in the transport process remains unclear. Here we present a lumen-facing cryo-EM structure of ZnT8 from Xenopus tropicalis (xtZnT8) in the presence of Zn at a luminal pH (5.5). Compared to a Zn-bound xtZnT8 structure at a cytosolic pH (7.5), the low-pH structure displays an empty transmembrane Zn-binding site with a disrupted coordination geometry. Combined with a Zn-binding assay our data suggest that protons may disrupt Zn coordination at the transmembrane Zn-binding site in the lumen-facing state, thus facilitating Zn release from ZnT8 into the lumen. PubMed: 36464198DOI: 10.1016/j.jsb.2022.107926 PDB entries with the same primary citation |
| Experimental method | ELECTRON MICROSCOPY (3.72 Å) |
Structure validation
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