A new type of peroxisomal acyl-coenzyme A synthetase from Arabidopsis thaliana has the catalytic capacity to activate biosynthetic precursors of jasmonic acid.
Arabidopsis thaliana contains a large number of genes that encode carboxylic acid-activating enzymes, including nine long-chain fatty acyl-CoA synthetases, four 4-coumarate:CoA ligases (4CL), and 25 4CL-like proteins of unknown biochemical function. Because of their high structural and sequence similarity with bona fide 4CLs and their highly hydrophobic putative substrate-binding pockets, the 4CL-like proteins At4g05160 and At5g63380 were selected for detailed analysis. Following heterologous expression, the purified proteins were subjected to a large scale screen to identify their preferred in vitro substrates. This study uncovered a significant activity of At4g05160 with medium-chain fatty acids, medium-chain fatty acids carrying a phenyl substitution, long-chain fatty acids, as well as the jasmonic acid precursors 12-oxo-phytodienoic acid and 3-oxo-2-(2'-pentenyl)-cyclopentane-1-hexanoic acid. The closest homolog of At4g05160, namely At5g63380, showed high activity with long-chain fatty acids and 12-oxo-phytodienoic acid, the latter representing the most efficiently converted substrate. By using fluorescent-tagged variants, we demonstrated that both 4CL-like proteins are targeted to leaf peroxisomes. Collectively, these data demonstrate that At4g05160 and At5g63380 have the capacity to contribute to jasmonic acid biosynthesis by initiating the beta-oxidative chain shortening of its precursors.
Schneider
Katja
K
Max Planck Institute for Plant Breeding Research, Department of Plant-Microbe Interactions, Carl-von-Linné-Weg 10, 50829 Köln, Germany.
Kienow
Lucie
L
Schmelzer
Elmon
E
Colby
Thomas
T
Bartsch
Michael
M
Miersch
Otto
O
Wasternack
Claus
C
Kombrink
Erich
E
Stuible
Hans-Peter
HP
D000085:Acetates / Q000378:metabolism; D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000166:cytology / Q000201:enzymology* / Q000235:genetics; D029681:Arabidopsis Proteins / Q000737:chemistry / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D003066:Coenzyme A Ligases / Q000737:chemistry / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D003517:Cyclopentanes / Q000378:metabolism*; D005227:Fatty Acids / Q000737:chemistry / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism; D015394:Molecular Structure; D054883:Oxylipins; D020675:Peroxisomes / Q000201:enzymology*; D010802:Phylogeny; D010937:Plant Growth Regulators / Q000378:metabolism*; D018515:Plant Leaves / Q000166:cytology / Q000201:enzymology; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment
D000085:Acetates; D029681:Arabidopsis Proteins; D003517:Cyclopentanes; D005227:Fatty Acids; D007527:Isoenzymes; D054883:Oxylipins; D010937:Plant Growth Regulators; D011993:Recombinant Fusion Proteins; C011006:jasmonic acid; C072239:methyl jasmonate; D003066:Coenzyme A Ligases; C501311:At4g05160 protein, Arabidopsis; C501312:At5g63380 protein, Arabidopsis