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Title | Cryo-EM structure of ACE2-SIT1 in complex with tiagabine. |
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Journal, issue, pages | J Biol Chem, Vol. 300, Issue 9, Page 107687, Year 2024 |
Publish date | Aug 17, 2024 |
Authors | Angelika Bröer / Ziwei Hu / Jędrzej Kukułowicz / Aditya Yadav / Ting Zhang / Lu Dai / Marek Bajda / Renhong Yan / Stefan Bröer / |
PubMed Abstract | The pharmacology of amino acid transporters in the SLC6 family is poorly developed compared to that of the neurotransmitter transporters. To identify new inhibitors of the proline transporter SIT1 ...The pharmacology of amino acid transporters in the SLC6 family is poorly developed compared to that of the neurotransmitter transporters. To identify new inhibitors of the proline transporter SIT1 (SLC6A20), its expression in Xenopus laevis oocytes was optimized. Trafficking of SIT1 was augmented by co-expression of angiotensin-converting enzyme 2 (ACE2) in oocytes but there was no strict requirement for co-expression of ACE2. A pharmacophore-guided screen identified tiagabine as a potent non-competitive inhibitor of SIT1. To understand its binding mode, we determined the cryo-electron microscopy (cryo-EM) structure of ACE2-SIT1 bound with tiagabine. The inhibitor binds close to the orthosteric proline binding site, but due to its size extends into the cytosolic vestibule. This causes the transporter to adopt an inward-open conformation, in which the intracellular gate is blocked. This study provides the first structural insight into inhibition of SIT1 and generates tools for a better understanding of the ACE2-SIT1 complex. These findings may have significance for SARS-CoV-2 binding to its receptor ACE2 in human lung alveolar cells where SIT1 and ACE2 are functionally expressed. |
External links | J Biol Chem / PubMed:39159813 / PubMed Central |
Methods | EM (single particle) |
Resolution | 3.34 - 3.8 Å |
Structure data | EMDB-37639, PDB-8wm3: EMDB-37868: The focused map of ACE2-SIT1 bound with tiagabine |
Chemicals | ChemComp-NAG: ChemComp-TGI: |
Source |
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Keywords | TRANSPORT PROTEIN/HYDROLASE / Transporter / inhibitors / TRANSPORT PROTEIN / TRANSPORT PROTEIN-HYDROLASE complex |