Ligand induced conformational changes of glutamine synthetase from Bacillus brevis bb g1 under non sporulating conditions - a fluorescence study

Abstract

Glutamine Synthetase from Bacillus brevis Bb G1was purified from pyruvate grown cells(GSpyr). The effect of ligands on the tryptophan fluorescence of the purified enzyme GSpyrwas investigated. With increasing concentrations of Lglutamine or glycine in GSpyr, a shift in emission maximum, change in fluorescence intensity and change in life times were observed compared to the emission maximum, fluorescence intensity and life times of GSpyr. These observations strongly support the possibility that GSpyr undergoes a conformational change on binding with ligands and each ligand produced different conformational changes in GSpyr. Also, different concentrations of each ligand produced different protein conformations in theenzymeGSpyr.