FIG. 3.

Activities of Cgs-AP and Cgs-βG fusion proteins. Alkaline phosphatase and β-galactosidase enzyme assays were performed with permeabilized cells of B. abortus strain 2308 carrying the fusion plasmids. The bar graph data are the means and standard errors (in units of enzyme activity) for two separate enzyme activity determinations for a single set of permeabilized cells. Similar results were obtained in three different experiments. Activities were corrected by subtracting the background activity of B. abortus 2308 harboring plasmid pBA or pBZ and were normalized by using the rate of synthesis of the fusion proteins, as described in Materials and Methods. The activities of Cgs-AP fusion proteins having very low activities are as follows: 39A, 0.668 ± 0.007 U; 156A, 0.653 ± 0.04 U; 597A, 0.212 ± 0.072 U; 926A, 0.231 ± 0.042 U; 1001A, 0.776 ± 0.081U; 1106A, 1.5 ± 0.218 U; 1815A, 0.573 ± 0.098 U; 2095A, 0.137 ± 0.045 U; and 2565A, 0.302 ± 0.05 U. The activities of Cgs-βG fusion proteins having low activities are as follows: 448Z, 109.2 ± 3.8 U; 848Z, 20.2 ± 0.1 U; and 967Z, 95.2 ± 2.3 U. An asterisk indicates that a plasmid expressing the fusion was not constructed. ND indicates that the fusion protein was not detected by immunoblotting.