(R)-Cysteate-nitrogen assimilation by Cupriavidus necator H16 with excretion of 3-sulfolactate: a patchwork pathway
In: Archives of microbiology, Jg. 194 (2012), Heft 11, S. 949-957
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academicJournal
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Zugriff:
Cupriavidus necator H16 grew exponentially with (R)-cysteate, a structural analogue of aspartate, as sole source of nitrogen in succinate-salts medium. Utilization of cysteate was quantitative and concomitant with growth and with the excretion of the deaminated product (R)-sulfolactate, which was identified thoroughly. The deaminative pathway started with transport of (R)-cysteate into the cell, which we attributed to an aspartate transporter. Transamination to sulfopyruvate involved an aspartate/ (R)-cysteate:2-oxoglutarate aminotransferase (Aoa/Coa) and regeneration of the amino group acceptor by NADP+-coupled glutamate dehydrogenase. Reduction of sulfopyruvate to (R)-sulfolactate was catalyzed by a (S)-malate/ (R)-sulfolactate dehydrogenase (Mdh/Sdh). Excretion of the sulfolactate could be attributed to the sulfite/organo-sulfonate exporter TauE, which was co-encoded and co-expressed, with sulfoacetaldehyde acetyltransferase (Xsc), though Xsc was irrelevant to the current pathway. The metabolic enzymes could be assayed biochemically. Aoa/Coa and Mdh/Sdh were highly enriched by protein separation, partly characterized, and the relevant locus-tags identified by peptide-mass fingerprinting. Finally, RT-PCR was used to confirm the transcription of all appropriate genes. We thus demonstrated that Cupriavidus necator H16 uses a patchwork pathway by recruitment of 'house-keeping' genes and sulfoacetaldehyde-degradative genes to scavenge for (R)-cysteate-nitrogen.
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(R)-Cysteate-nitrogen assimilation by Cupriavidus necator H16 with excretion of 3-sulfolactate: a patchwork pathway
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Autor/in / Beteiligte Person: | MAYER, Jutta ; DENGER, Karin ; HOLLEMEYER, Klaus ; SCHLEHECK, David ; COOK, Alasdair M |
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Zeitschrift: | Archives of microbiology, Jg. 194 (2012), Heft 11, S. 949-957 |
Veröffentlichung: | Heidelberg: Springer, 2012 |
Medientyp: | academicJournal |
Umfang: | print, 1 p |
ISSN: | 0302-8933 (print) |
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