Closed form of liganded glutamine-binding protein by rotational-echo double-resonance NMR

Rotational-echo double-resonance NMR has been used to determine internuclear distances in the complex of glutamine-binding protein and its ligand, l-glutamine. The distances between the ligand and Tyr185 are consistent with the results of molecular dynamics simulations constrained by three REDOR-determined distances to His156. This model is also consistent with six other REDOR-determined internuclear distances, most of which agree with values from the first report of an X-ray structure of the complex of glutamine-binding protein and l-glutamine.