Histidine carrier protein, molecular model

Molecular model of histidine carrier protein (PDB code: 1ptf). Ribbon diagram with His-15 shown as ball-and-stick model. HPR is part of the phospho-enolpyruvate-dependent sugar phospho-transferase system (PTS), a major carbohydrate active transport system moving certain hexoses across the cytoplasmic membrane of bacteria and mycoplasmas. The His-15 at the active site of HPR accepts a multi-enzyme system (Enzyme I) and transfers it to various sugar-specific PTS permeases.