title: Malonyl-CoA synthetase, encoded by ACYL ACTIVATING ENZYME13, is essential for growth and development of Arabidopsis.
abstract: Malonyl-CoA is the precursor for fatty acid synthesis and elongation. It is also one of the building blocks for the biosynthesis of some phytoalexins, flavonoids, and many malonylated compounds. In plants as well as in animals, malonyl-CoA is almost exclusively derived from acetyl-CoA by acetyl-CoA carboxylase (EC 6.4.1.2). However, previous studies have suggested that malonyl-CoA may also be made directly from malonic acid by malonyl-CoA synthetase (EC 6.2.1.14). Here, we report the cloning of a eukaryotic malonyl-CoA synthetase gene, Acyl Activating Enzyme13 (AAE13; At3g16170), from Arabidopsis thaliana. Recombinant AAE13 protein showed high activity against malonic acid (K(m) = 529.4 ± 98.5 μM; V(m) = 24.0 ± 2.7 μmol/mg/min) but little or no activity against other dicarboxylic or fatty acids tested. Exogenous malonic acid was toxic to Arabidopsis seedlings and caused accumulation of malonic and succinic acids in the seedlings. aae13 null mutants also grew poorly and accumulated malonic and succinic acids. These defects were complemented by an AAE13 transgene or by a bacterial malonyl-CoA synthetase gene under control of the AAE13 promoter. Our results demonstrate that the malonyl-CoA synthetase encoded by AAE13 is essential for healthy growth and development, probably because it is required for the detoxification of malonate.
authors.affiliation: Institute of Biological Chemistry, Washington State University, Pullman, Washington 99164-6340.
authors.forename: Hui
authors.initials: H
authors.lastname: Chen
authors.forename: Hyun Uk
authors.initials: HU
authors.lastname: Kim
authors.forename: Hua
authors.initials: H
authors.lastname: Weng
authors.forename: John
authors.initials: J
authors.lastname: Browse
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D017360:Arabidopsis / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D003066:Coenzyme A Ligases / Q000235:genetics / Q000378:metabolism*; D005227:Fatty Acids / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D005816:Genetic Complementation Test; D006801:Humans; D008314:Malonates / Q000378:metabolism / Q000633:toxicity; D008969:Molecular Sequence Data; D030821:Plants, Genetically Modified; D011401:Promoter Regions, Genetic; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D036226:Seedlings / Q000187:drug effects / Q000502:physiology; D016415:Sequence Alignment; D019802:Succinic Acid / Q000378:metabolism; D019076:Transgenes
chemical_list: D029681:Arabidopsis Proteins; D001426:Bacterial Proteins; D005227:Fatty Acids; D008314:Malonates; D011994:Recombinant Proteins; C030290:malonic acid; D019802:Succinic Acid; D003066:Coenzyme A Ligases; C021533:malonyl-CoA synthetase