7nnl
From Proteopedia
Cryo-EM structure of the KdpFABC complex in an E1-ATP conformation loaded with K+
Structural highlights
FunctionKDPA_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).[1] [2] [3] [4] Publication Abstract from PubMedKdpFABC, a high-affinity K(+) pump, combines the ion channel KdpA and the P-type ATPase KdpB to secure survival at K(+) limitation. Here, we apply a combination of cryo-EM, biochemical assays, and MD simulations to illuminate the mechanisms underlying transport and the coupling to ATP hydrolysis. We show that ions are transported via an intersubunit tunnel through KdpA and KdpB. At the subunit interface, the tunnel is constricted by a phenylalanine, which, by polarized cation-pi stacking, controls K(+) entry into the canonical substrate binding site (CBS) of KdpB. Within the CBS, ATPase coupling is mediated by the charge distribution between an aspartate and a lysine. Interestingly, individual elements of the ion translocation mechanism of KdpFABC identified here are conserved among a wide variety of P-type ATPases from different families. This leads us to the hypothesis that KdpB might represent an early descendant of a common ancestor of cation pumps. Deciphering ion transport and ATPase coupling in the intersubunit tunnel of KdpFABC.,Silberberg JM, Corey RA, Hielkema L, Stock C, Stansfeld PJ, Paulino C, Hanelt I Nat Commun. 2021 Aug 24;12(1):5098. doi: 10.1038/s41467-021-25242-x. PMID:34429416[5] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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