Journal of Biological Chemistry
Volume 286, Issue 13, 1 April 2011, Pages 11382-11390
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Plant Biology
Plant d-2-Hydroxyglutarate Dehydrogenase Participates in the Catabolism of Lysine Especially during Senescence*

https://doi.org/10.1074/jbc.M110.194175 Get rights and content
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d-2-Hydroxyglutarate dehydrogenase (d-2HGDH) catalyzes the specific and efficient oxidation of d-2-hydroxyglutarate (d-2HG) to 2-oxoglutarate using FAD as a cofactor. In this work, we demonstrate that d-2HGDH localizes to plant mitochondria and that its expression increases gradually during developmental and dark-induced senescence in Arabidopsis thaliana, indicating an enhanced demand of respiration of alternative substrates through this enzymatic system under these conditions. Using loss-of-function mutants in d-2HGDH (d2hgdh1) and stable isotope dilution LC-MS/MS, we found that the d-isomer of 2HG accumulated in leaves of d2hgdh1 during both forms of carbon starvation. In addition to this, d2hgdh1 presented enhanced levels of most TCA cycle intermediates and free amino acids. In contrast to the deleterious effects caused by a deficiency in d-2HGDH in humans, d2hgdh1 and overexpressing lines of d-2HGDH showed normal developmental and senescence phenotypes, indicating a mild role of d-2HGDH in the tested conditions. Moreover, metabolic fingerprinting of leaves of plants grown in media supplemented with putative precursors indicated that d-2HG most probably originates during the catabolism of lysine. Finally, the l-isomer of 2HG was also detected in leaf extracts, indicating that both chiral forms of 2HG participate in plant metabolism.

Amino Acid
Dehydrogenase
Energy Metabolism
Flavoproteins
Mitochondrial Metabolism
Amino Acid Catabolism
Carbon Starvation
d-2-Hydroxyglutarate Dehydrogenase
Plant Senescence
Tricarboxylic Acid Cycle

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*

This work was supported by Deutsche Forschungsgemeinschaft grants (to V. G. M. and A. P. M. W.) as part of the German Photorespiration Research Network Promics.

The on-line version of this article (available at http://www.jbc.org ) contains supplemental Fig. S1 and Tables S1–S4.

1

Both authors contributed equally to this work.