The phosphoenolpyruvate-dependent sugar phosphotransferase system (sugar PTS), a major carbohydrate active -transport system, catalyzes the phosphorylation of incoming sugar substrates concomitantly with their translocation across the cell membrane. The EIIB domain is phosphorylated by phospho-EIIA on a cysteinyl or histidyl residue, depending on the transported sugar. Then, it transfers the phosphoryl group to the sugar substrate concomitantly with the sugar uptake processed by the EIIC domain.