Structural highlights
Function
S23A1_MOUSE Sodium:L-ascorbate cotransporter. Mediates electrogenic uptake of vitamin C, with a stoichiometry of 2 Na(+) for each L-ascorbate (PubMed:36749388). Has retained some ancestral activity toward nucleobases such as urate, an oxidized purine. Low-affinity high-capacity sodium:urate cotransporter, may regulate serum urate levels by serving as a renal urate re-absorber (By similarity) (PubMed:36749388).[UniProtKB:Q9UHI7][1]
Publication Abstract from PubMed
Vitamin C (L-ascorbic acid) is an essential nutrient for human health, and its deficiency has long been known to cause scurvy. Sodium-dependent vitamin C transporters (SVCTs) are responsible for vitamin C uptake and tissue distribution in mammals. Here, we present cryogenic electron microscopy structures of mouse SVCT1 in both the apo and substrate-bound states. Mouse SVCT1 forms a homodimer with each protomer containing a core domain and a gate domain. The tightly packed extracellular interfaces between the core domain and gate domain stabilize the protein in an inward-open conformation for both the apo and substrate-bound structures. Vitamin C binds at the core domain of each subunit, and two potential sodium ions are identified near the binding site. The coordination of sodium ions by vitamin C explains their coupling transport. SVCTs probably deliver substrate through an elevator mechanism in combination with local structural arrangements. Altogether, our results reveal the molecular mechanism by which SVCTs recognize vitamin C and lay a foundation for further mechanistic studies on SVCT substrate transport.
Structural basis of vitamin C recognition and transport by mammalian SVCT1 transporter.,Wang M, He J, Li S, Cai Q, Zhang K, She J Nat Commun. 2023 Mar 13;14(1):1361. doi: 10.1038/s41467-023-37037-3. PMID:36914666[2]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Toyoda Y, Miyata H, Uchida N, Morimoto K, Shigesawa R, Kassai H, Nakao K, Tomioka NH, Matsuo H, Ichida K, Hosoyamada M, Aiba A, Suzuki H, Takada T. Vitamin C transporter SVCT1 serves a physiological role as a urate importer: functional analyses and in vivo investigations. Pflugers Arch. 2023 Apr;475(4):489-504. PMID:36749388 doi:10.1007/s00424-023-02792-1
- ↑ Wang M, He J, Li S, Cai Q, Zhang K, She J. Structural basis of vitamin C recognition and transport by mammalian SVCT1 transporter. Nat Commun. 2023 Mar 13;14(1):1361. PMID:36914666 doi:10.1038/s41467-023-37037-3
