computer-generated image of surface potential of
histidine phosphocarrier protein HPR (PDB code:
1pch),a component of the phosphoenolpyruvate-
dependent sugar phosphotransferase system (PTS), a
major carbohydrate active-transport system
responsible for transport of certain hexose
substrates across the cytoplasmic membrane of
bacteria and mycoplasmas. The imidazole group on
His-15 at the active site of HPR accepts a
multi-enzyme system (Enzyme I) and transfers it to
various sugar-specific PTS permeases.
