This title appears in the Scientific Report :
2011
Please use the identifier:
http://dx.doi.org/10.1128/JB.01295-10 in citations.
Corynebacterium glutamicum as a host for the synthesis and export of D-amino acids
Corynebacterium glutamicum as a host for the synthesis and export of D-amino acids
A number of d-amino acids occur in nature, and there is growing interest in their function and metabolism, as well as in their production and use. Here we use the well-established l-amino-acid-producing bacterium Corynebacterium glutamicum to study whether d-amino acid synthesis is possible and whet...
Saved in:
Personal Name(s): | Stäbler, N. |
---|---|
Oikawa, T. / Bott, M. / Eggeling, L. | |
Contributing Institute: |
Biotechnologie 1; IBT-1 |
Published in: | Journal of bacteriology, 193 (2011) S. 1702 - 1709 |
Imprint: |
Washington, DC
Soc.
2011
|
Physical Description: |
1702 - 1709 |
DOI: |
10.1128/JB.01295-10 |
PubMed ID: |
21257776 |
Document Type: |
Journal Article |
Research Program: |
Biotechnologie |
Series Title: |
Journal of Bacteriology
193 |
Subject (ZB): | |
Publikationsportal JuSER |
A number of d-amino acids occur in nature, and there is growing interest in their function and metabolism, as well as in their production and use. Here we use the well-established l-amino-acid-producing bacterium Corynebacterium glutamicum to study whether d-amino acid synthesis is possible and whether mechanisms for the export of these amino acids exist. In contrast to Escherichia coli, C. glutamicum tolerates d-amino acids added extracellularly. Expression of argR (encoding the broad-substrate-specific racemase of Pseudomonas taetrolens) with its signal sequence deleted results in cytosolic localization of ArgR in C. glutamicum. The isolated enzyme has the highest activity with lysine (100%) but also exhibits activity with serine (2%). Upon overexpression of argR in an l-arginine, l-ornithine, or l-lysine producer, equimolar mixtures of the d- and l-enantiomers accumulated extracellularly. Unexpectedly, argR overexpression in an l-serine producer resulted in extracellular accumulation of a surplus of d-serine (81 mM d-serine and 37 mM l-serine) at intracellular concentrations of 125 mM d-serine plus 125 mM l-serine. This points to a nonlimiting ArgR activity for intracellular serine racemization and to the existence of a specific export carrier for d-serine. Export of d-lysine relies fully on the presence of lysE, encoding the exporter for l-lysine, which is apparently promiscuous with respect to the chirality of lysine. These data show that d-amino acids can also be produced with C. glutamicum and that in special cases, due to specific carriers, even a preferential extracellular accumulation of this enantiomer is possible. |