Open AccessNo evidence of covalent modification of glutamine synthetase in the thermophilic phototropic bacterium Chloroflexus aurantiacus
Author(s) -
Kaulen Hildegard,
Klemme JobstHeinrich
Publication year - 1983
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.1983.tb00092.x
Subject(s) - rhodospirillales , rhodospirillaceae , glutamine synthetase , adenylylation , phototroph , biology , biochemistry , thermophile , bacteria , enzyme , photosynthesis , glutamine , biosynthesis , amino acid , genetics
Regulation of glutamine synthetase (GS) in the thermophilic green phototrophic bacterium, Chloroflexus aurantiacus , was studied. The enzyme was partially purified from cells grown photosynthetically in media with limiting (1 mM) or non‐limiting (10 mM) NH + 4 ‐concentrations. GS preparations from both cell types were indistinguishable in respect to pH‐optimum of GS‐transferase activity, sensitivity to feedback modifiers (AMP, L‐alanine, glycine) and lack of Mg‐inhibition of transferase activity. In contrast to results obtained with a GS preparation from the facultatively phototrophic bacterium, Rhodopseudomonas sphaeroides , the catalytic properties of Chloroflexus GS did not change during incubation with snake venom phosphodiesterase suggesting the absence of in vivo regulation of Chloroflexus GS by adenylylation/deadenylylation.