Structures of human SGLT in the occluded state reveal conformational changes during sugar transport.
Cui, W., Niu, Y., Sun, Z., Liu, R., Chen, L.(2023) Nat Commun 14: 2920-2920
- PubMed: 37217492 
- DOI: https://doi.org/10.1038/s41467-023-38720-1
- Primary Citation of Related Structures:  
7YNI, 7YNJ, 7YNK - PubMed Abstract: 
Sodium-Glucose Cotransporters (SGLT) mediate the uphill uptake of extracellular sugars and play fundamental roles in sugar metabolism. Although their structures in inward-open and outward-open conformations are emerging from structural studies, the trajectory of how SGLTs transit from the outward-facing to the inward-facing conformation remains unknown. Here, we present the cryo-EM structures of human SGLT1 and SGLT2 in the substrate-bound state. Both structures show an occluded conformation, with not only the extracellular gate but also the intracellular gate tightly sealed. The sugar substrate are caged inside a cavity surrounded by TM1, TM2, TM3, TM6, TM7, and TM10. Further structural analysis reveals the conformational changes associated with the binding and release of substrates. These structures fill a gap in our understanding of the structural mechanisms of SGLT transporters.
Organizational Affiliation: 
State Key Laboratory of Membrane Biology, College of Future Technology, Institute of Molecular Medicine, Peking University, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, 100871, Beijing, China.