Fluorescence study on ligand induced conformational changes of glutamine synthetase from Bacillus brevis Bb G1 under sporulating conditions
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Date
2015-02-18
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Plovdiv University Press “Paisii Hilendarski”
Abstract
Glutamine synthetase, an important enzyme of nitrogen metabolism, was purified under sporulating conditions (GSala). The effect of ligands on the tryptophan fluorescence of the purified enzyme GSala was investigated. With increasing concentrations of L-glutamine in GSala, a blue shift in emission maximum with an increase in fluorescence intensity and decrease in life times were observed compared to the emission maximum, fluorescence intensity and life times of GSala. With increasing concentrations of glycine in GSala, a shift in emission maximum, change in fluorescence intensity and change in lifetimes were observed compared to the emission maximum, fluorescence intensity and life times of GSala. These observations strongly support the possibility that GSala undergoes a conformational change on binding with ligands and each ligand produced different conformational changes in GSala. Also, different concentrations of each ligand produced different protein conformations in the enzyme GSala.
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Keywords
glutamine synthetase, fluorescence spectroscopy, conformational changes