EMD-36055

Single-particle
2.68 Å
EMD-36055 Deposition: 28/04/2023
Map released: 20/09/2023
Last modified: 23/10/2024
Overview 3D View Sample Experiment Validation Volume Browser Additional data Links
Overview 3D View Sample Experiment Validation Volume Browser Additional data Links

EMD-36055

Cryo-EM structure of hZnT7-Fab complex in zinc state 1, determined in heterogeneous conformations- one subunit in an inward-facing zinc-bound and the other in an outward-facing zinc-unbound conformation

EMD-36055

Single-particle
2.68 Å
EMD-36055 Deposition: 28/04/2023
Map released: 20/09/2023
Last modified: 23/10/2024
Overview 3D View Sample Experiment Validation Volume Browser Additional data Links
Sample Organism: Homo sapiens, Mus musculus
Sample: Human ZnT7-Fab complex
Fitted models: 8j80 (Avg. Q-score: 0.504)

Deposition Authors: Han BB, Inaba K , Watanabe S
Cryo-EM structures of human zinc transporter ZnT7 reveal the mechanism of Zn 2+ uptake into the Golgi apparatus.
Bui HB, Watanabe S , Nomura N , Liu K, Uemura T, Inoue M, Tsutsumi A , Fujita H, Kinoshita K, Kato Y, Iwata S , Kikkawa M , Inaba K
(2023) Nat Commun , 14 , 4770 - 4770
PUBMED: 37553324
DOI: doi:10.1038/s41467-023-40521-5
ISSN: 2041-1723
Abstract:
Zinc ions (Zn2+) are vital to most cells, with the intracellular concentrations of Zn2+ being tightly regulated by multiple zinc transporters located at the plasma and organelle membranes. We herein present the 2.2-3.1 Å-resolution cryo-EM structures of a Golgi-localized human Zn2+/H+ antiporter ZnT7 (hZnT7) in Zn2+-bound and unbound forms. Cryo-EM analyses show that hZnT7 exists as a dimer via tight interactions in both the cytosolic and transmembrane (TM) domains of two protomers, each of which contains a single Zn2+-binding site in its TM domain. hZnT7 undergoes a TM-helix rearrangement to create a negatively charged cytosolic cavity for Zn2+ entry in the inward-facing conformation and widens the luminal cavity for Zn2+ release in the outward-facing conformation. An exceptionally long cytosolic histidine-rich loop characteristic of hZnT7 binds two Zn2+ ions, seemingly facilitating Zn2+ recruitment to the TM metal transport pathway. These structures permit mechanisms of hZnT7-mediated Zn2+ uptake into the Golgi to be proposed.