Fatty Acid Biosynthesis in Mitochondria of Grasses

Malonyl-Coenzyme A Is Generated by a Mitochondrial-Localized Acetyl-Coenzyme A Carboxylase

authored by

Manfred Focke, Ellen Gieringer, Sabine Schwan, Lothar Jänsch, Stefan Binder, Hans Peter Braun

Abstract

We present biochemical evidence for the occurrence of a 250-kD multifunctional acetyl-coenzyme A carboxylase in barley (Hordeum vulgare) mitochondria. Organelles from 6-d-old barley seedlings were purified by differential centrifugation and Percoll density gradient centrifugation. Upon analysis by two-dimensional Blue-native (BN)/SDS-PAGE, an abundant 250-kD protein can be visualized, which runs at 500 kD on the native gel dimension. A similar 500-kD complex is present in etioplasts from barley. The mitochondrial 250-kD protein is biotinylated as indicated by specific reaction with an antibody directed against biotin. Peptide sequence analysis by electrospray ionization tandem mass spectrometry of the 250-kD proteins from both organellar fractions revealed amino acid sequences that are 100% identical to plastidic acetyl-coenzyme A carboxylase from wheat (Triticum aestivum). The 500-kD complex was also detected in wheat mitochondria, but is absent in mitochondrial fractions from Arabidopsis. Specific acetyl-coenzyme A carboxylation activity in barley mitochondria is higher than in etioplasts, suggesting an important role of mitochondria in fatty acid biosynthesis. Functional implications are discussed.

Organisation(s)

Institute of Plant Genetics

External Organisation(s)

Karlsruhe Institute of Technology (KIT)
Helmholtz Centre for Infection Research (HZI)
Ulm University

Type

Article

Journal

Plant physiology

Volume

133

Pages

875-884

No. of pages

10

ISSN

0032-0889

Publication date

10.2003

Publication status

Published

Peer reviewed

Yes

ASJC Scopus subject areas

Physiology, Genetics, Plant Science

Electronic version(s)

https://doi.org/10.1104/pp.103.027375 (Access: Open)