In vitro, phosphorylates various substrates such as EmbR, PepE, MmaA4, Pyk, LldD and GroEL2. ATP + L-seryl-[protein] = ADP + H(+) + O-phospho-L-seryl-[protein] ATP + L-threonyl-[protein] = ADP + H(+) + O-phospho-L-threonyl-[protein] Activated by certain divalent metal cations, such as cobalt, manganese, nickel or magnesium. Zinc or iron ions do not affect activity. Homodimer. Autophosphorylated. Dephosphorylated by PstP. Belongs to the protein kinase superfamily. Ser/Thr protein kinase family.