Arabidopsis FAD2 gene encodes the enzyme that is essential for polyunsaturated lipid synthesis
| Autor: | John Joseph Okuley, Narendra S. Yadav, Jonathan Lightner, Kenneth A. Feldmann, Ellen Lark, John Browse |
|---|---|
| Rok vydání: | 1994 |
| Předmět: |
DNA
Bacterial Fatty Acid Desaturases Oxidoreductases Acting on CH-CH Group Donors Transcription Genetic Iron Molecular Sequence Data Arabidopsis Plant Science Biology Genes Plant Linoleic Acid Complementary DNA Amino Acid Sequence Phosphatidylcholine desaturase Cloning Molecular Peptide sequence Alleles Plant Proteins chemistry.chemical_classification Base Sequence Sequence Homology Amino Acid Genetic Complementation Test Structural gene alpha-Linolenic Acid Fatty acid DNA Cell Biology Cold Temperature Stearoyl-CoA Desaturase Fatty acid desaturase Linoleic Acids chemistry Biochemistry Mutation biology.protein Research Article Polyunsaturated fatty acid |
| Zdroj: | The Plant Cell. 6:147-158 |
| ISSN: | 1532-298X 1040-4651 |
| DOI: | 10.1105/tpc.6.1.147 |
| Popis: | The polyunsaturated fatty acids linoleate and alpha-linolenate are important membrane components and are the essential fatty acids of human nutrition. The major enzyme responsible for the synthesis of these compounds is the plant oleate desaturase of the endoplasmic reticulum, and its activity is controlled in Arabidopsis by the fatty acid desaturation 2 (fad2) locus. A fad2 allele was identified in a population of Arabidopsis in which mutations had been created by T-DNA insertions. Genomic DNA flanking the T-DNA was cloned by plasmid rescue and used to isolate cDNA and genomic clones of FAD2. A cDNA containing the entire FAD2 coding sequence was expressed in fad2 mutant plants and shown to complement the mutant fatty acid phenotype. The deduced amino acid sequence from the cDNA showed homology to other plant desaturases, and this confirmed that FAD2 is the structural gene for the desaturase. Gel blot analyses of FAD2 mRNA levels showed that the gene is expressed throughout the plant and suggest that transcript levels are in excess of the amount needed to account for oleate desaturation. Sequence analysis identified histidine-rich motifs that could contribute to an iron binding site in the cytoplasmic domain of the protein. Such a position would facilitate interaction between the desaturase and cytochrome b5, which is the direct source of electrons for the desaturation reaction, but would limit interaction of the active site with the fatty acyl substrate. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|