Cyclic di-AMP traps proton-coupled K⁺ transporters of the KUP family in an inward-occluded conformation.

ABSTRACT: Cyclic di-AMP is the only known essential second messenger in bacteria and archaea, regulating different proteins indispensable for numerous physiological processes. In particular, it controls various potassium and osmolyte transporters involved in osmoregulation. In Bacillus subtilis, the K⁺/H⁺ symporter KimA of the KUP family is inactivated by c-di-AMP. KimA sustains survival at potassium limitation at low external pH by mediating potassium ion uptake. However, at elevated intracellular K⁺ concentrations, further K⁺ accumulation would be toxic. In this study, we reveal the molecular basis of how c-di-AMP binding inhibits KimA. We report cryo-EM structures of KimA with bound c-di-AMP in detergent solution and reconstituted in amphipols. By combi

SUBMITTER: Fuss MF 

PROVIDER: S-EPMC10284832 | biostudies-literature | 2023 Jun

REPOSITORIES: biostudies-literature