ISSN:
1432-072X
Keywords:
Glutamine synthetase
;
Deadenylylation/adenylylation in vitro
;
Structural properties
;
Rhodopseudomonas sphaeroides
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract Glutamine synthetase (GS) of Rhodopseudomonas sphaeroides is regulated by adenylylation and deadenylylation. The extent of adenylylation/deadenylylation of the enzyme in cell free extracts was influenced by inorganic phosphate (P i), α-ketoglutarate, ATP and other nucleotides. While P i and α-ketoglutarate stimulated deadenylylation, ATP and other nucleotides enhanced adenylylation of the GS. By using proper combinations of the effectors and incubation conditions, any desired adenylylation state of GS could be adjusted in vitro. The enzyme was purified to electrophoretic homogenity by three steps including affinity chromatography on 5′-AMP-Sepharose. Adenylylated and deadenylylated enzyme showed different UV-spectra and isoelectric points. The native enzyme had a molecular weight of 600,000, deadenylylated subunits of 50,000±1,000. Electron microscopic investigations revealed a dodecameric arrangement of subunits in two hexameric planes.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00415001
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