title: Solid-state REDOR NMR distance measurements at the ligand site of a bacterial chemotaxis membrane receptor.
abstract: The Escherichia coli serine receptor senses serine levels in the environment and transmits this information across the bacterial inner membrane to modulate a protein phosphorylation cascade which controls swimming behavior. Solid-state nuclear magnetic resonance (NMR) has been used to characterize specific structural features of the ligand binding site interactions in the intact, membrane-bound Ser receptor. Rotational-echo double-resonance (REDOR) experiments on [15N]Ser bound to a [1-13C]Phe-receptor preparation are used to measure distances between the ligand amino group and the carbonyls of two phenylalanine residues in the ligand binding pocket. The results indicate two 4.0 +/- 0.2 A distances, in excellent agreement with the X-ray crystal structure of a soluble fragment of the homologous aspartate receptor [Milburn et al. (1991) Science 254, 1342-1347]. These results confirm the similarity of the binding sites of the Asp and Ser receptors, and demonstrate the feasibility of using solid-state NMR measurements to obtain specific structural information on the 120 kDa intact receptor for probing transmembrane signaling mechanisms.
authors.affiliation: Department of Chemistry, University of Massachusetts, Amherst 01003, USA.
authors.forename: J
authors.initials: J
authors.lastname: Wang
authors.forename: Y S
authors.initials: YS
authors.lastname: Balazs
authors.forename: L K
authors.initials: LK
authors.lastname: Thompson
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry* / Q000378:metabolism; D001665:Binding Sites; D002633:Chemotaxis; D004926:Escherichia coli / Q000737:chemistry* / Q000378:metabolism; D008024:Ligands; D009682:Magnetic Resonance Spectroscopy; D010649:Phenylalanine / Q000737:chemistry; D017459:Receptors, Amino Acid / Q000737:chemistry* / Q000378:metabolism; D012694:Serine / Q000737:chemistry* / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D008024:Ligands; D017459:Receptors, Amino Acid; C038039:serine receptor; D012694:Serine; D010649:Phenylalanine