Dynamic frequency shifts of complexed ligands: An NMR study of D--1-13C,1-2H-glucose complexed to the Escherichia coli periplasmic glucose/galactose receptor.
The 13C multiplet structure of D--1-13C,1-2H-glucose complexed to the Escherichia coli periplasmic glucose/galactose receptor has been studied as a function of temperature. Asymmetric multiplet patterns observed are shown to arise from dynamic frequency shifts. Multiplet asymmetry contributions resulting from shift anisotropy-dipolar cross correlations were found to be small, with optimal fits of the data corresponding to small, negative values of the correlation factor, chiCD-CSA. Additional broadening at higher temperatures most probably results from ligand exchange between free and complexed states. Effects of internal motion are also considered theoretically, and indicate that the order parameter for the bound glucose is >/=0.9.
Gabel
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Laboratory of Structural Biology, MR-01, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina 27709, USA.
Luck
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Werbelow
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LG
London
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D001426:Bacterial Proteins; D002628:Chemoreceptor Cells / Q000737:chemistry*; D004926:Escherichia coli / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy; D011956:Receptors, Cell Surface / Q000737:chemistry*
D001426:Bacterial Proteins; D011956:Receptors, Cell Surface; C039707:galactose receptor; C027786:glucose receptor