FIG. 1.

Identification of Anabaena KdpB homolog. Proteins were extracted from A. torulosa cultures grown in N-supplemented (lanes 1 and 2) or N-deficient (lanes 3 and 4) conditions in BG-11/K5 (lanes 2 and 3) or BG-11/K0 (lanes 1 and 4) medium for 3 days. Equal amounts of protein (150 μg) were resolved by sodium dodecyl sulfate–10% polyacrylamide gel electrophoresis (100 V for 1 h followed by 200 V for 3.5 h) and then electroblotted. The blots were allowed to cross-react with a primary anti-E. coli KdpB antiserum followed by a secondary anti-rabbit immunoglobulin G coupled to alkaline phosphatase.