Disease relevance of AT2G04540

• In vitro assays using extracts of CY244 containing all E. coli FAS components, except that KAS I and II were replaced by mtKAS, gave C(4)-C(18) fatty acids exhibiting a bimodal distribution with peaks at C(8) and C(14)-C(16) [1].

High impact information on AT2G04540

• Intracellular targeting using green fluorescent protein, Western blot, and deletion analyses identified an N-terminal signal conveying mtKAS into mitochondria [1].
• In the first or priming condensation reaction of de novo fatty acid synthesis, purified His-tagged mtKAS efficiently utilized malonyl-ACP, but not acetyl-CoA as primer substrate [1].
• Thus, mtKAS with its broad chain length specificity accomplishes all condensation steps in mitochondrial fatty acid synthesis, whereas in plastids three KAS enzymes are required [1].
• The Leu337 residue is conserved among plant and bacterial KAS proteins, and in the crystal structures of E. coli KAS I and KAS II, this leucine abuts a phenylalanine whose imidazole ring extends into the substrate binding cavity causing the fatty acid chain to bend [2].
• In the presence of the KAS I inhibitor cerulenin, however, transgenic seed extracts extended 6:0- and 8:0-ACP at a rate four- to fivefold greater than extracts from untransformed plants, whereas no difference was observed in extension of 14:0- and 16:0-ACP [3].

Biological context of AT2G04540

• The combined activities of KAS A1 and FatB thioesterases appear to determine the C. wrightii phenotype [3].
• The deduced amino acid sequence showed significant similarities to other KAS IIIs although the leek sequence had some notable differences in regions otherwise completely conserved in dicots [4].
• Crystal structure data for Escherichia coli beta-ketoacyl synthase (KAS) I with C(10) and C(12) fatty acid substrates bound in conjunction with results from mutagenizing residues in the active site leads to a model for catalysis [5].

References