FIG. 3.

(A) Localization of KdpD in Anabaena sp. strain L-31. The antiserum raised against purified KdpD(6His) was used to detect the KdpD protein from Anabaena sp. strain L-31. Anabaena sp. strain L-31 membrane (M) and cytosolic (C) fractions from cells grown in BG11K5 medium were prepared as described (1). About 200 μg of protein was loaded in lanes 2 to 5, while 150 ng of purified Anabaena KdpD(6His) was loaded in lane 1. Lanes 1 to 3 were probed with the Anabaena KdpD(6His) antiserum, while lanes 4 and 5 were probed with the control preimmune serum. (B) Effect of K⁺ limitation on kdpD expression in Anabaena sp. strain L-31. Anabaena sp. strain L-31 cells were grown in BG11K5 medium and then transferred to BG11 medium containing 0 mM or 5 mM K⁺. At the times indicated, the cells were harvested, membranes were isolated, 200 μg total membrane protein was electrophoresed, and Anabaena KdpD (shown by the arrow) was detected as before.