Plants Possess a Cyclic Mitochondrial Metabolic Pathway similar to the Mammalian Metabolic Repair Mechanism Involving Malate Dehydrogenase and l-2-Hydroxyglutarate Dehydrogenase
Artikel i vetenskaplig tidskrift, 2014

Enzymatic side reactions can give rise to the formation of wasteful and toxic products that are removed by metabolite repair pathways. In this work, we identify and characterize a mitochondrial metabolic repair mechanism in Arabidopsis thaliana involving malate dehydrogenase (mMDH) and l-2-hydroxyglutarate dehydrogenase (l-2HGDH). We analyze the kinetic properties of both A. thaliana mMDH isoforms, and show that they produce l-2-hydroxyglutarate (l-2HG) from 2-ketoglutarate (2-KG) at low rates in side reactions. We identify A. thaliana l-2HGDH as a mitochondrial FAD-containing oxidase that converts l-2HG back to 2-KG. Using loss-of-function mutants, we show that the electrons produced in the l-2HGDH reaction are transferred to the mitochondrial electron transport chain through the electron transfer protein (ETF). Thus, plants possess the biochemical components of an l-2HG metabolic repair system identical to that found in mammals. While deficiencies in the metabolism of l-2HG result in fatal disorders in mammals, accumulation of l-2HG in plants does not adversely affect their development under a range of tested conditions. However, orthologs of l-2HGDH are found in all examined genomes of viridiplantae, indicating that the repair reaction we identified makes an essential contribution to plant fitness in as yet unidentified conditions in the wild. © 2015 The Author 2015.

l-2-Hydroxyglutarate

Arabidopsis

l-2-Hydroxyglutarate dehydrogenase

Malate dehydrogenase

Metabolite repair

Författare

M. Hüdig

Heinrich Heine Universitat

A. Maier

Heinrich Heine Universitat

I. Scherrers

Heinrich Heine Universitat

L. Seidel

Heinrich Heine Universitat

E. E. W. Jansen

VU University Medical Center

T. Mettler-Altmann

Heinrich Heine Universitat

Martin Engqvist

Chalmers, Kemi- och bioteknik, Livsvetenskaper, Systembiologi

V. G. Maurino

Heinrich Heine Universitat

Plant and Cell Physiology

0032-0781 (ISSN) 1471-9053 (eISSN)

Vol. 56 1820-1830

Ämneskategorier

Biokemi och molekylärbiologi

Bioinformatik och systembiologi

DOI

10.1093/pcp/pcv108