A short intrinsically disordered region at KtrB's N-terminus facilitates allosteric regulation of K⁺ channel KtrAB.

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

SUBMITTER: Stautz J 

PROVIDER: S-EPMC12059179 | biostudies-literature | 2025 May

REPOSITORIES: biostudies-literature