FIG. 2.

Phosphorylation of MBP by PknB. Purified PknB was incubated with the surrogate kinase substrate MBP and [γ-³²P]ATP in the presence or absence of Mn²⁺ or Mg²⁺. The reaction products were resolved on a 12% SDS-PAGE gel that was stained with Coomassie blue (not shown) and visualized by autoradiography. (A) Time-dependent phosphorylation of MBP. (B) Concentration-dependent phosphorylation with different Mn²⁺ or Mg²⁺ concentrations. The positions and masses (in kDa) of protein standards are indicated on the left. Besides phosphorylation of MBP autophosphorylation of PknB is visible.