FIGURE 2.

CO₂ binds Rv1625c in vitro and activates in vivo. a, Rv1625c^204–443-specific activity (n = 6) was plotted against increasing Mn²⁺. The assay mixture contained 1.8 μm protein and 200 μm Mn²⁺-ATP, pH 6.5, and 20 mm NaCl (triangles) or 20 mm NaHCO₃ (7.7 mm CO₂, squares). b, recovered CO₂ from a binding assay in the presence of Rv1625c^204–443, bovine serum albumin (BSA), or buffer alone. c, recovered CO₂ from a binding assay in the presence of Slr1991^120–337 wild type (wt), Slr1991^120–337 D137A D181A (Δmetal), BSA, or buffer alone. d, cAMP-dependent lacZ activity in E. coli under control (vector) conditions or in the presence of Rv1625c^204–443 in samples treated with air or 10% (v/v) CO₂ in air (n = 9; *, p < 0.05). The y axis denotes the concentration of ortho-nitrophenol (ONP) in the lacZ assays performed.