Cross-species phosphotransfer profiling of phosphorelay histidine kinases and Spo0B phosphotransferases.

Assessment of phosphotransfer from (A) B. subtilis Spo0B or (B) D. acetoxidans Spo0B to Spo0A proteins from C. acetobutylicum, D. acetoxidans, or B. subtilis, as indicated above each lane. In these reactions, both Bacillar (A) and Clostridial (B) Spo0B specificity residues enable phosphotransfer to Spo0A proteins from both phosphorelays and direct phosphorylation architectures. (C) Phosphotransfer was examined from B. subtilis KinA (lanes 1–5) or D. acetoxidans Dtox_1918 (lanes 6–10) to Spo0A or Spo0F proteins, as indicated. The observed interactions are consistent with conservation of Spo0A specificity, with minor shifts, across pathway architectures and taxonomic classes. In each reaction, following autophosphorylation, all proteins combined were incubated for 5 minutes (see text for details). See Table 2 for abbreviations.