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Zusammenfassung:
For many years understanding of the metabolism of Escherichia coli has been one of the main topics in microbiology research. Many details have been elucidated about the regulation of nitrogen and carbon metabolism but little is known about their coordination. Probably the nitrogen metabolic phosphotransferase system PTSNtr is a component of this tuning. It consists of enzyme INtr (EINtr encoded by ptsP), NPr (encoded by ptsO) and enzyme IINtr (EIIANtr encoded by ptsN). On the one hand the genes ptsO and ptsN are located on the same operon as rpoN, the nitrogen dependent sigma factor. On the other hand the PTSNtr consists of the phosphoryl transfer chain, PEP -> EINtr -> NPr -> EIIANtr, similar to the carbohydrate PTS. Both phosphoryl transfer chains can exchange phosphate groups.
To analyse the function of the PTSNtr we investigated growth rates and acetate formation of Escherichia coli LJ110 and of derivatives mutated in the PTSNtr under different carbon conditions in batch experiments. Our results showed a higher acetate yield in strains deleted in ptsN. To provided our observation we used real time PCR for analyzing expression of genes connected to acetate formation.
