Nitrogenase Activity and Membrane Electrogenesis in the Cyanobacterium Anabaena variabilis Kütz

RNA processing of nitrogenase transcripts in the cyanobacterium Anabaena variabilis.

Little is known about the regulation of nitrogenase genes in cyanobacteria. Transcription of the nifH1 and vnfH genes, encoding dinitrogenase reductases for the heterocyst-specific Mo-nitrogenase and the alternative V-nitrogenase, respectively, was studied by using a lacZ reporter. Despite evidence for a transcription start site just upstream of nifH1 and vnfH, promoter fragments that included ...

The Expression of a Third Nitrogenase in the Cyanobacterium Anabaena variabilis

Physiological experiments indicate that Anabaena variabilis can express either a Vor a Fe-nitrogenase in addition to the conventional, Mo-containing enzyme complex. The occur­ rence o f the Fe-nitrogenase in A. variabilis can also be concluded from D N A -D N A hybridiza­ tion experiments using cloned anfW or nifW probes coding for the smaller subunit (= nitroge­ nase reductase) o f the Fe-nitr...

Bioenergetics Studies of the Cyanobacterium Anabaena variabilis

A cell-free system exhibiting both photophosphorylation (P /2e = 1) and oxidative phosphoryla­ tion (P/O up to 0 .8 ) is described for the cyanobacterium Anabaena variabilis. NADH and N A D PH were found to be equally effective as electron donors for oxidative phosphorylation. Low concentrations of U H D B T , an inhibitor of the cytochrome blc complex of mitochondria and chloroplasts. were fou...

Potassium ion transport and electrogenesis in Anabaena variabilis.

Characterization of genes for a second Mo-dependent nitrogenase in the cyanobacterium Anabaena variabilis.

Anabaena variabilis ATCC 29413 is a filamentous heterocystous cyanobacterium that fixes nitrogen under a variety of environmental conditions. Under aerobic growth conditions, nitrogen fixation depends upon differentiation of heterocysts and expression of either a Mo-dependent nitrogenase or a V-dependent nitrogenase in those specialized cells. Under anaerobic conditions, a second Mo-dependent n...