Apr 6, 1976

Glutamine synthetase adenylyltransferase from Escherichia coli: purification and physical and chemical properties

C E Caban, A Ginsburg


The glutamine synthetase adenylyltransferase (EC, WHIch catalyzes the adenylylation and deadenylylation of glutamine synthetase in E. coli, has been stabilized and purified 2200-fold to apparent homogeneity. Sedimentation and electrophoresis studies show that the native enzyme is a single polypeptide chain of 115,000 +/- 5000 molecular weight with an isoelectric pH (PL) OF 4.98, a sedimentation coefficient (S20.w0) of 5.6S, and a molar frictional coefficient (f/f0) of 1.52. An alpha-helical content of approximately equal to 25% and approximately equal to 28% beta-pleated sheet and approximately equal to 47% random coil structures were estimated from circular dichroism measurements. The amino acid composition of the protein has been determined. The intrinsic tryptophanyl residue flourescence of adenylyltransferase is two fold greater than that of L-tryptophan; this property has been used to monitor ligand-induced conformational changes in the enzyme. Activators of the adenylylation reaction (ATP, L-glutamine, or the E. coli PII regulatory protein) produced an enhancement of fluorescence; alpha-ketoglutarate, an inhibitor of adenylylation and an activator of deadenulylation, caused a net decrease in fluorescence. The ad...Continue Reading

  • References
  • Citations23


  • We're still populating references for this paper, please check back later.

Mentioned in this Paper

Alkalescens-Dispar Group
Alpha Ketoglutarate
Glutamate-Ammonia Ligase
GLUL gene
Fluorescence Spectroscopy
Protein Conformation
Purification Aspects
Molar Tooth

Related Feeds

Cajal Bodies & Gems

Cajal bodies or coiled bodies are dense foci of coilin protein. Gemini of Cajal bodies, or gems, are microscopically similar to Cajal bodies. It is believed that Cajal bodies play important roles in RNA processing while gems assist the Cajal bodies. Find the latest research on Cajal bodies and gems here.