GltS, the sodium-coupled L-glutamate uptake system of Corynebacterium glutamicum: identification of the corresponding gene and impact on L-glutamate production.
A screening procedure was established to identify Corynebacterium glutamicum transposon mutants with an altered L-glutamate excretion behaviour. By this microtiter plate-based approach seven non- or less excreting C. glutamicum strains and two hyper-excreters were found. The subsequently carried out molecular analysis of a hyper-producing clone led to the identification of the gltS gene, which codes for the sodium-coupled secondary L-glutamate uptake system in C. glutamicum. Characterization of a gltS deletion strain revealed that this transporter has a weak but significant impact on L-glutamate production induced by biotin limitation in the wild type. Obviously, GltS leads to the re-uptake of excreted L-glutamate causing a futile cycle. In accord with this hypothesis, the overexpression of gltS decreased L-glutamate production.
Trötschel
C
C
Institut für Biochemie der Universität zu Köln, Zülpicher-Strasse 47, 50674 Cologne, Germany.
Kandirali
S
S
Diaz-Achirica
P
P
Meinhardt
A
A
Morbach
S
S
Krämer
R
R
Burkovski
A
A
D026922:Amino Acid Transport Systems, Acidic / Q000235:genetics* / Q000378:metabolism; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D001710:Biotin / Q000378:metabolism; D003352:Corynebacterium / Q000235:genetics* / Q000378:metabolism; D004926:Escherichia coli / Q000378:metabolism; D017353:Gene Deletion; D015964:Gene Expression Regulation, Bacterial; D015723:Gene Library; D018390:Gene Targeting; D005798:Genes, Bacterial; D018698:Glutamic Acid / Q000378:metabolism*; D016254:Mutagenesis, Insertional; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D012964:Sodium / Q000378:metabolism; D027981:Symporters / Q000235:genetics* / Q000378:metabolism
D026922:Amino Acid Transport Systems, Acidic; D001426:Bacterial Proteins; D011993:Recombinant Fusion Proteins; D027981:Symporters; D018698:Glutamic Acid; D001710:Biotin; D012964:Sodium