Functional characterization of K⁺ transporter in cyanobacteria Synechocystis sp. PCC6803

Abstract

Potassium ion is major cation in cell of organization, and is supplied into the cells by several transport systems. Bacteria and plants have K⁺ transporters and K⁺ channels, which are involved in environmental response and signal transduction. The homologous genes have been isolated from several organisms, and their function and structure have been studied to date. The gene encode homologous proteins that share with high homology for plant Na⁺/K⁺ transporter (HKT family) and Vibrio alginolyticus K⁺ transporter (KtrB) have been isolated from cyanobacteria Synechocystis sp. PCC6803. The strain which has a mutation at the gene did not show K⁺ uptake transport activity. When the K⁺ Ktr/HKT homologous protein was expressed in K⁺ uptake deficient E. coli, the K⁺ transport was impaired by addition of CCCP.