Global flexibility in a sensory receptor: a site-directed cross-linking approach.
The aspartate receptor of Escherichia coli and Salmonella typhimurium is a cell surface sensory transducer that binds extracellular aspartate and sends a transmembrane signal to the inside of the bacterium. The flexibility and allostery of this receptor was examined by placing sulfhydryl groups as potential cross-linking sites at targeted locations in the protein. Seven different mutant receptors were constructed, each containing a single cysteine residue at a different position in the primary structure. Intramolecular disulfide bond formation within oligomers of these mutant receptors is shown to trap structural fluctuations and to detect ligand-induced changes in structure. The results indicate that the receptor oligomer has a flexible, dynamic structure which undergoes a global change upon aspartate binding.
Falke
J J
JJ
Koshland
D E
DE
D000494:Allosteric Regulation; D001426:Bacterial Proteins / Q000502:physiology*; D002633:Chemotaxis; D003001:Cloning, Molecular; D003545:Cysteine; D004220:Disulfides; D046911:Macromolecular Substances; D008565:Membrane Proteins / Q000502:physiology*; D009154:Mutation; D011487:Protein Conformation; D017459:Receptors, Amino Acid; D017981:Receptors, Neurotransmitter / Q000502:physiology*; D013329:Structure-Activity Relationship
D001426:Bacterial Proteins; D004220:Disulfides; D046911:Macromolecular Substances; D008565:Membrane Proteins; D017459:Receptors, Amino Acid; D017981:Receptors, Neurotransmitter; C031959:aspartic acid receptor; D003545:Cysteine