Member of the two-component regulatory system PrrB/PrrA that is involved specifically in early intracellular multiplication of Mycobacterium and is essential for its viability (PubMed:11953357, PubMed:22081401). Functions as a sensor protein kinase which is autophosphorylated at a histidine residue and transfers its phosphate group to the conserved aspartic acid residue in the regulatory domain of PrrA (PubMed:14702417, PubMed:29101285). In turn, PrrA binds to the upstream promoter regions of target genes including itself to positively regulate their expression (PubMed:14702417). ATP + protein L-histidine = ADP + protein N-phospho-L-histidine. By nitrogen-limiting conditions. Autophosphorylated.