Fig. 1.

Dual-state Ca²⁺ transport of YfkE. (A) ⁴⁵Ca²⁺ transport activity of YfkE measured using ISO vesicles, showing biphasic kinetics when vesicles were pretreated with 1 mM EGTA (red), and Michelis–Menton kinetics using vesicles without EGTA treatment (black). A cartoon model of the transport assay shows that YfkE (green bar) transport Ca²⁺ into the ISO vesicle (gray circles) using an outward H⁺ gradient. (B) Eadie–Hofstee plots of data from A. Data fitting was carried out using the software Graphpad Prism 7. Error bars represent SDs from three independent experiments.