Removal of Mn2+ induces dissociation of glutamine synthetase fromStreptomyces aureofaciens

Removal of Mn2+ by EDTA treatment converted dodecameric glutamine synthetase (GS) fromStreptomyces aureofaciens into inactive subunits but did not affect significantly their conformation. However, when fractionated by gel filtration FPLC, the Mn2+-free subunits showed a 7-fold increase ofA280, proba...

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Bibliographic Details
Published in:Folia microbiologica 1997-12, Vol.42 (6), p.539-543
Main Authors: Nguyen, K. T., Nguyen, L. T., Kopecký, J., Běhal, V.
Format: Article
Language:English
Subjects:
Calcium ions
Carbon dioxide
Cations
Cobalt
Conformation
Divalent cations
Enzymes
Ethylenediaminetetraacetic acids
Gel filtration
Glutamate-ammonia ligase
Glutamine
Gram-positive bacteria
Magnesium
Microbiology
Protein structure
Tertiary structure
Zinc
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Summary:Removal of Mn2+ by EDTA treatment converted dodecameric glutamine synthetase (GS) fromStreptomyces aureofaciens into inactive subunits but did not affect significantly their conformation. However, when fractionated by gel filtration FPLC, the Mn2+-free subunits showed a 7-fold increase ofA280, probably due to a significant alteration in their tertiary structure. Mn2+ reduced theA280 of the subunits and promoted their reaggregation to form active GS. Mg2+ or Ca2+ but not Co2+ or Zn2+ might have similar effects. The results suggest that specific divalent cations might play a crucial role in stabilizing subunit interactions as well as the conformation of the individual subunits inStreptomyces GS. The role of specific divalent cations in the regulation of GS turnover is discussed.
ISSN:0015-5632
1874-9356
DOI:10.1007/BF02815461