Interaction of extrinsic fluorescent probes with E. coli glutamine synthetase.
Binding of 2-p-toluidinylnaphthalene-6-sulfonate (TNS) to adenylylated (E--11) glutamine synthetase is cooperative and time-dependent, with 3 dye sites per subunit. In fluorescence polarization experiments TNS and pyrene butyrate give normalized Perrin plots that indicate a symmetrical arrangement of dye excited state dipoles, relative to the rotational axis of the oblate ellipsoid of the dodecameric native enzyme.
D004926:Escherichia coli / Q000201:enzymology*; D005974:Glutamate-Ammonia Ligase; D009282:Naphthalenesulfonates; D011721:Pyrenes; D013050:Spectrometry, Fluorescence
D009282:Naphthalenesulfonates; D011721:Pyrenes; D005974:Glutamate-Ammonia Ligase