Three dimensional structures of the ligand-binding domain of the wild-type aspartate receptor with and without aspartate and biochemical characterization of the intact receptor

摘要: The aspartate receptor of Salmonella typhimurium and Escherichia coli is a transmembrane receptor which mediates chemotactic response to specific chemicals. These chemicals include aspartate, phenol, and divalent cations, Ni and Co . The bacterial chemotaxis system allows the bacteria to sense nutrients and toxins and adjust its motile behavior based on the detection of these chemicals. Biochemical studies have shown that the mechanism of transmembrane signal transmission in this system is based on a conformational change within the dimeric receptor and is not based on a change in its oligomeric state (Milligan and Koshland, 1988). Thus, crystallographic studies were initiated to characterize the conformational change occurring upon aspartate binding.