Beta-ketoacyl-acyl carrier protein synthase IV: a key enzyme for regulation of medium-chain fatty acid synthesis in Cuphea lanceolata seeds
| Autor: | Burkhardt Siegfried Schütt, Amine Abbadi, Friedrich Spener, Brigitte Loddenkötter, Monika Brummel |
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| Rok vydání: | 2001 |
| Předmět: |
DNA
Complementary Molecular Sequence Data Plant Science Cuphea lanceolata Gene Expression Regulation Enzymologic Cuphea Substrate Specificity chemistry.chemical_compound Biosynthesis Gene Expression Regulation Plant 3-Oxoacyl-(Acyl-Carrier-Protein) Synthase Genetics Escherichia coli Cloning Molecular Fatty acid synthesis chemistry.chemical_classification biology Acyl carrier protein synthase Fatty Acids Decanoic acid Sequence Analysis DNA biology.organism_classification Enzyme chemistry Biochemistry Seeds biology.protein lipids (amino acids peptides and proteins) |
| Zdroj: | Planta. 215(5) |
| ISSN: | 0032-0935 |
| Popis: | With the aim of elucidating the mechanisms involved in the biosynthesis of medium-chain fatty acids in Cuphea lanceolata Ait., a crop accumulating up to 90% decanoic acid in seed triacylglycerols, cDNA clones of a beta-ketoacyl-acyl carrier protein (ACP) synthase IV (clKAS IV, EC 2.3.1.41) were isolated from C. lanceolata seed embryos. The amino acid sequence deduced from clKAS IV cDNA showed 80% identity to other plant KAS II-type enzymes, 55% identity towards plant KAS I and over 90% towards other Cuphea KAS IV-type sequences. Recombinant clKAS IV was functionally overexpressed in Escherichia coli, and substrate specificity of purified enzyme showed strong preference for elongation of short-chain and medium-chain acyl-ACPs (C4- to C10-ACP) with nearly equal activity. Further elongation steps were catalysed with distinctly less activity. Moreover, short- and medium-chain acyl-ACPs exerted a chain-length-specific and concentration-dependent substrate inhibition of clKAS IV. Based on these findings a regulatory mechanism for medium-chain fatty acid synthesis in C. lanceolata is presented. |
| Databáze: | OpenAIRE |
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