30UU

Structure of NaCT in NaCl

Summary for 30UU

• Entry DOI: 10.2210/pdb30uu/pdb
• EMDB information: 58072
• Descriptor: Na(+)/citrate cotransporter, 2-acetamido-2-deoxy-beta-D-glucopyranose (2 entities in total)
• Functional Keywords: complex, membrane protein
• Biological source: Homo sapiens (human)
• Total number of polymer chains: 2
• Total formula weight: 126664.04

Authors

Sauer, D.B.,Song, J.,Marden, J.J.,Wang, B.,Rice, W.J.,Wang, D.N. (deposition date: 2026-05-13, release date: 2026-07-29)

Primary citation

Sauer, D.B.,Song, J.,Marden, J.J.,Wang, B.,Sowerby, K.,Sudar, J.C.,Rice, W.J.,Wang, D.N.
Structures of the human sodium-citrate cotransporter NaCT with and without substrates.
Biorxiv, 2026

PubMed Abstract: The human sodium-citrate cotransporter NaCT imports various tri- and dicarboxylates into the cell as TCA cycle intermediates. This substrate uptake process is driven by an inward sodium gradient. The protein is a member of the Divalent Anion-Sodium Symporter (DASS) family. Whereas extensive biochemical and structural studies have been carried out for NaCT, how the substrate binding and translocation is coupled to the sodium gradient remains unclear. Here using single particle cryo-electron microscopy, we determined the structures of the human NaCT protein in three states: sodium-free, in the presence of sodium, and sodium- and substrate-bound. These structures suggest a simultaneous binding mechanism for sodium-substrate coupling, distinct from the sequential binding, conformational selection mechanism previously observed for the bacterial DASS protein VcINDY.

PubMed: 42465234
DOI: 10.64898/2026.07.08.737274

Experimental method

ELECTRON MICROSCOPY (2.51 Å)