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| Home > Publications database > Co-metabolism of a Non-Growth Substrate: L-Serine Utilization by Corynebacterium glutamicum |
| Home > Publications database > Co-metabolism of a Non-Growth Substrate: L-Serine Utilization by Corynebacterium glutamicum |
| Journal Article | PreJuSER-36935 |
; ; ;
2004
Soc.
Washington, DC [u.a.]
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Please use a persistent id in citations: http://hdl.handle.net/2128/2418 doi:10.1128/AEM.70.12.7148-7155.2004
Abstract: Despite its key position in central metabolism, L-serine does not support the growth of Corynebacterium glutamicum. Nevertheless, during growth on glucose, L-serine is consumed at rates up to 19.4 +/- 4.0 nmol min(-1) (mg [dry weight])(-1), resulting in the complete consumption of 100 mM L-serine in the presence of 100 mM glucose and an increased growth yield of about 20%. Use of 13C-labeled L-serine and analysis of cellularly derived metabolites by nuclear magnetic resonance spectroscopy revealed that the carbon skeleton of L-serine is mainly converted to pyruvate-derived metabolites such as L-alanine. The sdaA gene was identified in the genome of C. glutamicum, and overexpression of sdaA resulted in (i) functional L-serine dehydratase (L-SerDH) activity, and therefore conversion of L-serine to pyruvate, and (ii) growth of the recombinant strain on L-serine as the single substrate. In contrast, deletion of sdaA decreased the L-serine cometabolism rate with glucose by 47% but still resulted in degradation of L-serine to pyruvate. Cystathionine beta-lyase was additionally found to convert L-serine to pyruvate, and the respective metC gene was induced 2.4-fold under high internal L-serine concentrations. Upon sdaA overexpression, the growth rate on glucose is reduced 36% from that of the wild type, illustrating that even with glucose as a single substrate, intracellular L-serine conversion to pyruvate might occur, although probably the weak affinity of L-SerDH (apparent Km, 11 mM) prevents substantial L-serine degradation.
Keyword(s): Bacterial Proteins: genetics (MeSH) ; Bacterial Proteins: metabolism (MeSH) ; Carbon Isotopes: metabolism (MeSH) ; Corynebacterium glutamicum: growth & development (MeSH) ; Corynebacterium glutamicum: metabolism (MeSH) ; Culture Media (MeSH) ; Gene Deletion (MeSH) ; Glucose: metabolism (MeSH) ; L-Serine Dehydratase: genetics (MeSH) ; L-Serine Dehydratase: metabolism (MeSH) ; Magnetic Resonance Spectroscopy (MeSH) ; Oligonucleotide Array Sequence Analysis (MeSH) ; Serine: metabolism (MeSH) ; Bacterial Proteins ; Carbon Isotopes ; Culture Media ; Glucose ; Serine ; L-Serine Dehydratase ; J
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