Phosphorylation of HPr by HPr Kinase in Gluconobacter oxydans 621H

DNA sequencing has revealed that Gluconobacter oxydans may contain an incomplete phosphoenolpyruvate: carbohydrate phosphotransferase system (PTS), but the function of individual members of the system remains unknown. Here we demonstrated that the predicted histidine protein HPr, an essential component of PTS, can be phosphorylated by a predicted HPr kinase in G. oxydans, where Ser54 in HPr is the site responsible for such a phosphorylation. The discovery implies that G. oxydans may regulate PTS activity in a way similar to that identified in some Gram-positive bacteria with low GC content.