The phosphotransferase system (PTS) of Streptomyces coelicolor

HPr, the histidine‐containing phosphocarrier protein of the bacterial phosphotransferase system (PTS) controls sugar uptake and carbon utilization in low‐GC Gram‐positive bacteria and in Gram‐negative bacteria. We have purified HPr from Streptomyces coelicolor cell extracts. The N‐terminal sequence matched the product of an S. coelicolor orf , designated ptsH , sequenced as part of the S. coelicolor genome sequencing project. The ptsH gene appears to form a monocistronic operon. Determination of the evolutionary relationship revealed that S. coelicolor HPr is equally distant to all known HPr and HPr‐like proteins. The presumptive phosphorylation site around histidine 15 is perfectly conserved while a second possible phosphorylation site at serine 47 is not well‐conserved. HPr was overproduced in Escherichia coli in its native form and as a histidine‐tagged fusion protein. Histidine‐tagged HPr was purified to homogeneity. HPr was phosphorylated by its own enzyme I (EI) and heterologously phosphorylated by EI of Bacillus subtilis and Staphylococcus aureus , respectively. This phospho enol pyruvate‐dependent phosphorylation was absent in an HPr mutant in which histidine 15 was replaced by alanine. Reconstitution of the fructose‐specific PTS demonstrated that HPr could efficiently phosphorylate enzyme II Fructose . HPr‐P could also phosphorylate enzyme II Glucose of B. subtilis , enzyme II Lactose of S. aureus , and IIA Mannitol of E. coli . ATP‐dependent phosphorylation was detected with HPr kinase/phosphatase of B. subtilis . These results present the first identification of a gene of the PTS complement of S. coelicolor , providing the basis to elucidate the role(s) of HPr and the PTS in this class of bacteria.