FIG 4.

Phosphorylation and DNA binding properties of mutant proteins. (A) Left panel, autophosphorylation of DevR proteins was carried out using acetyl-[³²P]phosphate as described in Materials and Methods. The percent phosphorylation of mutant proteins relative to that of WT protein was derived by phosphorimaging and densitometric analysis. Right panel, DevS₂₀₁-mediated phosphotransfer to DevR WT and mutant proteins. The percent efficiency of mutant DevR phosphorylation was calculated as described above. DevS₂₀₁ (∼15 μM) was autophosphorylated in the presence of [γ-³²P]ATP prior to addition to the reaction mixture. (B) Interaction of DevR with target promoter DNA. P+S box oligonucleotide sequences of the tgs1-Rv3131 promoter region were incubated with WT or mutant protein. The percentage of DNA bound is plotted versus protein concentration. A representative result from 3 experiments is shown.