FIGURE 1.

Hjc is phosphorylated by three eukaryotic-like protein kinases (ePKs) SiRe_0171, SiRe_2030, and SiRe_2056KD from S. islandicus in vitro. Each ePK (2 μM) was incubated with 5 μM Hjc in the reaction mixture containing [γ -³²P]ATP at 65^°C for 30 min (see the Materials and Methods). After reaction, the samples were analyzed by 15% SDS-PAGE. The experiments were performed for at least three times for each enzyme. Left panel, a representative image (15% gel) showing the activities of the ePKs autophosphorylation and phosphorylation on Hjc. The three ePKs that are able to phosphorylate Hjc are labeled with asterisks. Right panel, quantification of the phosphorylation activity of SiRe_0171, SiRe_2030, and SiRe_2056KD on Hjc. The vertical axis shows relative signal strength, the ratio of phosphorylated Hjc by each ePK divided by that by SiRe_2030. Standard deviation is indicated with error bars.