Applied Microbiology and Biotechnology

, 76:691

Glutamate production by Corynebacterium glutamicum: dependence on the oxoglutarate dehydrogenase inhibitor protein OdhI and protein kinase PknG

Authors

  • Christian Schultz
    • Institut für Biotechnologie 1Forschungszentrum Jülich
  • Axel Niebisch
    • Institut für Biotechnologie 1Forschungszentrum Jülich
  • Lena Gebel
    • Institut für Biotechnologie 1Forschungszentrum Jülich
    • Institut für Biotechnologie 1Forschungszentrum Jülich
Applied Microbial and Cell Physiology

DOI: 10.1007/s00253-007-0933-9

Cite this article as:
Schultz, C., Niebisch, A., Gebel, L. et al. Appl Microbiol Biotechnol (2007) 76: 691. doi:10.1007/s00253-007-0933-9

Abstract

We recently showed that the activity of the 2-oxoglutarate dehydrogenase complex (ODHC) in Corynebacterium glutamicum is controlled by a novel regulatory mechanism that involves a 15-kDa protein called OdhI and serine/threonine protein kinase G (PknG). In its unphosphorylated state, OdhI binds to the E1 subunit (OdhA) of ODHC and, thereby, inhibits its activity. Inhibition is relieved by phosphorylation of OdhI at threonine-14 by PknG under conditions requiring high ODHC activity. In this work, evidence is provided that the dephosphorylation of phosphorylated OdhI is catalyzed by a phospho-Ser/Thr protein phosphatase encoded by the gene cg0062, designated ppp. As a decreased ODHC activity is important for glutamate synthesis, we investigated the role of OdhI and PknG for glutamate production under biotin limitation and after addition of Tween-40, penicillin, or ethambutol. A ΔodhI mutant formed only 1–13% of the glutamate synthesized by the wild type. Thus, OdhI is essential for efficient glutamate production. The effect of a pknG deletion on glutamate synthesis was dependent on the induction conditions. Under strong biotin limitation and in the presence of ethambutol, the ΔpknG mutant showed significantly increased glutamate production, offering a new way to improve production strains.

Keywords

Corynebacterium glutamicumGlutamateOdhI2-Oxoglutarate dehydrogenaseOxoglutarate dehydrogenase inhibitorPknGSerine/threonine protein kinase

Abbreviations

cdw

cell dry weight

PknG

serine/threonine protein kinase G

ODHC

2-oxoglutarate dehydrogenase complex

OdhI

oxoglutarate dehydrogenase inhibitor protein

TCA cycle

tricarboxylic acid cycle

Copyright information

© Springer-Verlag 2007