PMR studies of the substrate induced conformational change of glutamine binding protein from E. coli

The substrate induced conformational change of glutamine binding protein isolated from E. coli has been studied by high resolution proton magnetic resonance spectroscopy. The addition of L-glutamine to a protein solution caused a marked change in the proton magnetic resonance spectrum. The chemical shifts of several resonances were considerably different for the free and complexed protein. The line width of the methyl protons decreased considerably with the addition of substrate indicating that the environment of a sizeable percentage of the methyl groups is different. The kinetics of binding as well as a possible mode of action of the binding proteins will be discussed.