FIG. 3.

Phosphorylation of PurA by PknB. The phosphorylation reaction was performed in the presence or absence of PknB as described in Materials and Methods. The His tag of both PknB and PurA was cleaved to exclude the possibility of a nonspecific in vitro phosphorylation effect. All reaction products were analyzed on a 12% SDS-PAGE gel, stained with Coomassie blue, and subjected to autoradiography. Lane 1 shows phosphorylation of PurA in the presence of PknB. Lane 2 contained the control without PknB. The positions and masses (in kDa) deduced from comparison with protein standards are indicated on the left.