Description
The nitrate reductase of unicellular cyanobacterium Synechococcus elongatus strain PCC 7942 is a molybdoprotein [1] and has been shown to be repressed by ammonium [2] and to be sensitive towards tungsten, which poisons the enzyme by replacing molybdenum [1, 3], whereas addition of the latter to a medium containing tungsten can rescue the activity of the enzyme. In Synechocystis sp. strain PCC 6803 the gene sll1454 (narB) encoding a functional nitrate reductase has already been deleted by Baebprasert et al. to check whether the hydrogenase and the nitrate reductase compete for the same electrons in this strain [4], however, the phenotype of the sll1454 knock out mutant strain concerning the assimilation of nitrate as the only available nitrogen source as well as the effect of tungsten to the molybdoenzyme in the wild type has not been analyzed so far. In this work we deleted sll1454 by a neomycin phosphate transferase in direct and complementary orientation and both mutant strains lost the capacity to grow in a medium with nitrate as sole nitrogen source but grew well in medium (without molybdenum or tungsten) containing ammonium instead. Replacing molybdenum by tungsten in this medium impaired but did not completely inhibit the growth of the wild type of Synechocystis sp. strain PCC 6803, indicating the cells kept molybdenum within their nitrate reductase even though the cells had been cultivated in the absence of both nitrate and molybdenum for several generations.| Period | 21 Aug 2022 |
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| Event title | 17th International Symposium on Phototrophic Prokaryotes (ISPP2022) |
| Event type | Conference |
| Location | Liverpool, United KingdomShow on map |
| Degree of Recognition | International |