An Intracellular Pathway Controlled by the N-terminus of the Pump Subunit Inhibits the Bacterial KdpFABC Ion Pump in High K⁺ Conditions.

ABSTRACT: The heterotetrameric bacterial KdpFABC transmembrane protein complex is an ion channel-pump hybrid that consumes ATP to import K⁺ against its transmembrane chemical potential gradient in low external K⁺ environments. The KdpB ion-pump subunit of KdpFABC is a P-type ATPase, and catalyses ATP hydrolysis. Under high external K⁺ conditions, K⁺ can diffuse into the cells through passive ion channels. KdpFABC must therefore be inhibited in high K⁺ conditions to conserve cellular ATP. Inhibition is thought to occur via unusual phosphorylation of residue Ser162 of the TGES motif of the cytoplasmic A domain. It is proposed that phosphorylation most likely traps KdpB in an inactive E1-P like conformation, but the molecular mechanism of phosphory

SUBMITTER: Dubey V 

PROVIDER: S-EPMC8286422 | biostudies-literature | 2021 Jul

REPOSITORIES: biostudies-literature