5MRW
Structure of the KdpFABC complex
Summary for 5MRW
| Entry DOI | 10.2210/pdb5mrw/pdb |
| Descriptor | Potassium-transporting ATPase potassium-binding subunit, Potassium-transporting ATPase ATP-binding subunit, Potassium-transporting ATPase KdpC subunit, ... (8 entities in total) |
| Functional Keywords | membrane protein complex potassium transport p-type atpase skt channel, hydrolase |
| Biological source | Escherichia coli More |
| Total number of polymer chains | 12 |
| Total formula weight | 465934.02 |
| Authors | Huang, C.,Pedersen, B.P.,Stokes, D.L. (deposition date: 2016-12-27, release date: 2017-06-21, Last modification date: 2020-07-29) |
| Primary citation | Huang, C.S.,Pedersen, B.P.,Stokes, D.L. Crystal structure of the potassium-importing KdpFABC membrane complex. Nature, 546:681-685, 2017 Cited by PubMed Abstract: Cellular potassium import systems play a fundamental role in osmoregulation, pH homeostasis and membrane potential in all domains of life. In bacteria, the kdp operon encodes a four-subunit potassium pump that maintains intracellular homeostasis, cell shape and turgor under conditions in which potassium is limiting. This membrane complex, called KdpFABC, has one channel-like subunit (KdpA) belonging to the superfamily of potassium transporters and another pump-like subunit (KdpB) belonging to the superfamily of P-type ATPases. Although there is considerable structural and functional information about members of both superfamilies, the mechanism by which uphill potassium transport through KdpA is coupled with ATP hydrolysis by KdpB remains poorly understood. Here we report the 2.9 Å X-ray structure of the complete Escherichia coli KdpFABC complex with a potassium ion within the selectivity filter of KdpA and a water molecule at a canonical cation site in the transmembrane domain of KdpB. The structure also reveals two structural elements that appear to mediate the coupling between these two subunits. Specifically, a protein-embedded tunnel runs between these potassium and water sites and a helix controlling the cytoplasmic gate of KdpA is linked to the phosphorylation domain of KdpB. On the basis of these observations, we propose a mechanism that repurposes protein channel architecture for active transport across biomembranes. PubMed: 28636601DOI: 10.1038/nature22970 PDB entries with the same primary citation |
| Experimental method | X-RAY DIFFRACTION (2.9 Å) |
Structure validation
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