Modification of the pII protein in response to carbon and nitrogen availability in filamentous heterocystous cyanobacteria |
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| Authors: | Sylviane Liotenberg Douglas Campbell Anne-Marie Castets Jean Houmard Nicole Tandeau de Marsac |
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| Institution: | Unitéde Physiologie Microbienne, Département de Biochimie et Génétique Moléculaire, Institut Pasteur, 28 rue du Docteur Roux, 75724 Paris Cedex 15, France |
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| Abstract: | Abstract In the filamentous cyanobacterium Calothrix PCC 7504, which fixes N2 aerobically, the modification state of the regulatory PII protein (GlnB) was shown to depend on nitrogen and carbon availability, as observed in the unicellular non-fixing strain Synechococcus PCC 7942. However, the conditions for modifications, the time dependence of the process and the electrophoretic behavior of the native PII isoforms differed somewhat between the two strains. In another strain, Calothrix PCC 7601, which has lost the capability to fix N2, PII was modified only if ammonia plus an inhibitor of glutamine synthetase were present. It is proposed that: (i) the behavior of the PII proteins depends upon the physiological properties of the strains; and (ii) the modification system of PII per se may differ between the two cyanobacterial genera. |
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| Keywords: | Calothrix PCC 7504 Calothrix PCC 7601 Carbon assimilation Nitrogen assimilation Post-translational modification Cell differentiation |
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