Dealing with the sulfur part of cysteine

four enzymaticsteps degrade L-cysteine to pyruvate and thiosulfate in Arabidopsis mitochondria

authored by

Saskia Höfler, Christin Lorenz, Tjorven Busch, Mascha Brinkkötter, Takayuki Tohge, Alisdair R. Fernie, Hans Peter Braun, Tatjana M. Hildebrandt

Abstract

Amino acid catabolism is essential for adjusting pool sizes of free amino acids and takes part in energy production as well as nutrient remobilization. The carbon skeletons are generally converted to precursors or intermediates of the tricarboxylic acid cycle. In the case of cysteine, the reduced sulfur derived from the thiol group also has to be oxidized in order to prevent accumulation to toxic concentrations. Here we present a mitochondrial sulfur catabolic pathway catalyzing the complete oxidation of l-cysteine to pyruvate and thiosulfate. After transamination to 3-mercaptopyruvate, the sulfhydryl group from l-cysteine is transferred to glutathione by sulfurtransferase 1 and oxidized to sulfite by the sulfur dioxygenase ETHE1. Sulfite is then converted to thiosulfate by addition of a second persulfide group by sulfurtransferase 1. This pathway is most relevant during early embryo development and for vegetative growth under light-limiting conditions. Characterization of a double mutant produced from Arabidopsis thaliana T-DNA insertion lines for ETHE1 and sulfurtransferase 1 revealed that an intermediate of the ETHE1 dependent pathway, most likely a persulfide, interferes with amino acid catabolism and induces early senescence.

Organisation(s)

Institute of Plant Genetics

External Organisation(s)

Max Planck Institute of Molecular Plant Physiology (MPI-MP)

Type

Article

Journal

Physiologia plantarum

Volume

157

Pages

352-366

No. of pages

15

ISSN

0031-9317

Publication date

23.04.2016

Publication status

Published

Peer reviewed

Yes

ASJC Scopus subject areas

Physiology, Genetics, Plant Science, Cell Biology

Electronic version(s)

https://doi.org/10.1111/ppl.12454 (Access: Closed)