6hrb

Cryo-EM structure of the KdpFABC complex in an E2 inward-facing state (state 2)Cryo-EM structure of the KdpFABC complex in an E2 inward-facing state (state 2)

6hrb, resolution 4.00Å Show:Asymmetric Unit Biological Assembly Structural highlights 6hrb is a 4 chain structure with sequence from Ecoli. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: Related: 6hra Gene: kdpA, b0698, JW0686 (ECOLI), kdpB, b0697, JW0685 (ECOLI), kdpC, b0696, JW0684 (ECOLI), kdpF, b4513, JW0687 (ECOLI) Activity: Potassium-transporting ATPase, with EC number 3.6.3.12 Experimental data: Check Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function [KDPF_ECOLI] Part of the high-affinity ATP-driven potassium transport (or Kdp) system, which catalyzes the hydrolysis of ATP coupled with the electrogenic transport of potassium into the cytoplasm (PubMed:23930894). This subunit may be involved in stabilization of the complex (PubMed:10608856). [KDPA_ECOLI] Part of the high-affinity ATP-driven potassium transport (or Kdp) system, which catalyzes the hydrolysis of ATP coupled with the electrogenic transport of potassium into the cytoplasm (PubMed:2849541, PubMed:8499455, PubMed:23930894). This subunit binds and transports the potassium across the cytoplasmic membrane (PubMed:7896809). [KDPC_ECOLI] Part of the high-affinity ATP-driven potassium transport (or Kdp) system, which catalyzes the hydrolysis of ATP coupled with the electrogenic transport of potassium into the cytoplasm (PubMed:2849541, PubMed:8499455, PubMed:23930894). This subunit acts as a catalytic chaperone that increases the ATP-binding affinity of the ATP-hydrolyzing subunit KdpB by the formation of a transient KdpB/KdpC/ATP ternary complex (PubMed:21711450). [KDPB_ECOLI] Part of the high-affinity ATP-driven potassium transport (or Kdp) system, which catalyzes the hydrolysis of ATP coupled with the electrogenic transport of potassium into the cytoplasm (PubMed:2849541, PubMed:8499455, PubMed:23930894). This subunit is responsible for energy coupling to the transport system (PubMed:16354672). Publication Abstract from PubMed P-type ATPases ubiquitously pump cations across biological membranes to maintain vital ion gradients. Among those, the chimeric K(+) uptake system KdpFABC is unique. While ATP hydrolysis is accomplished by the P-type ATPase subunit KdpB, K(+) has been assumed to be transported by the channel-like subunit KdpA. A first crystal structure uncovered its overall topology, suggesting such a spatial separation of energizing and transporting units. Here, we report two cryo-EM structures of the 157 kDa, asymmetric KdpFABC complex at 3.7 A and 4.0 A resolution in an E1 and an E2 state, respectively. Unexpectedly, the structures suggest a translocation pathway through two half-channels along KdpA and KdpB, uniting the alternating-access mechanism of actively pumping P-type ATPases with the high affinity and selectivity of K(+) channels. This way, KdpFABC would function as a true chimeric complex, synergizing the best features of otherwise separately evolved transport mechanisms. Cryo-EM structures of KdpFABC suggest a K(+) transport mechanism via two inter-subunit half-channels.,Stock C, Hielkema L, Tascon I, Wunnicke D, Oostergetel GT, Azkargorta M, Paulino C, Hanelt I Nat Commun. 2018 Nov 26;9(1):4971. doi: 10.1038/s41467-018-07319-2. PMID:30478378 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.