7ZPR

KtrAB complex with N-terminal deletion of KtrB 1-19

Summary for 7ZPR

• Entry DOI: 10.2210/pdb7zpr/pdb
• Related: 7zp9 7zpo
• EMDB information: 14851 14859 14862
• Descriptor: Ktr system potassium uptake protein A, Ktr system potassium uptake protein B, MAGNESIUM ION, ... (5 entities in total)
• Functional Keywords: potassium transport, membrane protein, transporter
• Biological source: Vibrio alginolyticus; More
• Total number of polymer chains: 12
• Total formula weight: 384108.18

Authors

Vonck, J.,Stautz, J. (deposition date: 2022-04-28, release date: 2023-05-10, Last modification date: 2026-05-20)

Primary citation

Stautz, J.,Griwatz, D.,Kaltwasser, S.,Mehdipour, A.R.,Ketter, S.,Thiel, C.,Wunnicke, D.,Schrecker, M.,Mills, D.J.,Hummer, G.,Vonck, J.,Hanelt, I.
A short intrinsically disordered region at KtrB's N-terminus facilitates allosteric regulation of K + channel KtrAB.
Nat Commun, 16:4252-4252, 2025

PubMed Abstract: K homeostasis is crucial for bacterial survival. The bacterial K+ channel KtrAB is regulated by the binding of ADP and ATP to the cytosolic RCK subunits KtrA. While the ligand-induced conformational changes in KtrA are well described, the transmission to the gating regions within KtrB is not understood. Here, we present a cryo-EM structure of the ADP-bound, inactive KtrAB complex from Vibrio alginolyticus, which resolves part of KtrB's N termini. They are short intrinsically disordered regions (IDRs) located at the interface of KtrA and KtrB. We reveal that these IDRs play a decisive role in ATP-mediated channel opening, while the closed ADP-bound state does not depend on the N-termini. We propose an allosteric mechanism, in which ATP-induced conformational changes within KtrA trigger an interaction of KtrB's N-terminal IDRs with the membrane, stabilizing the active and conductive state of KtrAB.

PubMed: 40335548
DOI: 10.1038/s41467-025-59546-z

Experimental method

ELECTRON MICROSCOPY (3.56 Å)