Glucose/Galactose Binding Protein (GBP) is a receptor in the chemosensory pathway of bacterial chemotaxis. GBP consists of two domains, each of which contains a beta-sheet packed between alpha-helices. The binding cleft is between the two hinged domains. Signal transduction begins in the periplasmic compartment where GBP is located. Binding of glucose or galatose by GBP causes a large amplitude conformational change that encapsulates the ligand. This allows GBP to bind to a transmembrane receptor initiating the remainder of the chemosensory pathway that regulates the bacterial flagellar motor and determines swimming behavior of the cell in response to chemical atractants or repellents