Fig 3.

Biochemical characterization of pkaR mutant strains. (A) Western blot analysis using a polyclonal antibody raised against M. rouxii PKAR (anti-R) of samples semipurified with cAMP-agarose from wt, ΔR2, and ΔR3 strains grown under aerobic conditions (left panel) and from wt and ΔR4 heterokaryotic strains from shift conditions (overnight growth in anaerobiosis and a 3-h shift to aerobiosis) (right panel). (B) PKAC activity was measured in the absence (□) or in the presence (■) of cAMP in semipurified samples from wild-type (wt) and ΔR2 strains grown under aerobic conditions. The data shown correspond to five assays, performed with independent preparations. Values are represented as means ± SEM from four replicates for each assay. (C) Binding activity measured in crude extracts from the wt, ΔR2, ΔR3, and ΔR4 strains grown under aerobic conditions (left panel) and from wt and ΔR4 strains after a shift from anaerobic to aerobic conditions (right panel).