Corrigendum to “Heterologous production of GLA and SDA by expression of an Echium plantagineum Δ6-desaturase gene” [Plant Sci. 170 (2006) 665–673]

Caenorhabditis elegans Δ12-Desaturase FAT-2 Is a Bifunctional Desaturase Able to Desaturate a Diverse Range of Fatty Acid Substrates at the Δ12 and Δ15 Positions

“…Expression of Genes in Yeast and Gas Chromatography Analysis-Plasmids were introduced into yeast strain S288C (11) cells by heat shock as described previously (12). Yeast feeding with different exogenous fatty acids was essentially as described previously (12).…”

“…Yeast feeding with different exogenous fatty acids was essentially as described previously (12). FAMEs were analyzed with a Agilent N6890 GC on a 60-m BPX70 column (0.25-mm inner diameter, 0.25-m film thickness, SGE), or Thermo Polaris Q GC-MS on a 30-m BPX70 column.…”

“…Identification of peaks was based on comparison of retention time with standard FAME and confirmed with MS acquired and processed with Xcalibur TM software from Thermo Electron Corporation. Double bond positions in the FAME were confirmed with 2,4-dimethyloxazoline (DMOX) adducts by derivatizing the FAMEs with 2-amino-2-methyl-propanol at 190°C overnight, cooling, and acidifying with 0.1 N HCl before extracting with dichloromethane (13), and analyzed as described previously for FAMEs (12).…”

“…) (3) whereas FAT-1 was shown to be a ⌬15-desaturase acting on 6 fatty acid LA, for example, to form ␣-linolenic acid (3, C18:3 ⌬9, 12,15 ) (4 -6). Fatty acid desaturases possess at least five specificities: chemoselectivity (desaturation versus hydroxylation), regioselectivity (double bond position), stereoselectivity (cis versus trans), chain length specificity, and acyl carrier specificity (acyl-CoA versus acyl-lipid substrate).…”

Consensus Mutagenesis and Ancestral Reconstruction Provide Insight into the Substrate Specificity and Evolution of the Front-End Δ6-Desaturase Family

“…Very few high-resolution structures of membrane-bound fatty acid desaturases have been determined, none of which are of Δ6-desaturases, and these enzymes cannot be easily purified in an active form. Sequence-based modeling and topology studies have nonetheless provided cursory information about the organization of these enzymes, generally predicting a four-transmembrane helix (TMH) topology that resembles that of the few crystallized Δ9-desaturases. − These TMHs form one portion of the enzymes’ desaturase domain, which also contains the enzyme active site and three conserved histidine-rich motifs (His boxes) that are thought to coordinate a di-iron center. − Δ6-Desaturases are also known to require a fused b 5 cytochrome domain at their N-terminus for their activity, which functions as an electron donor during catalysis. − However, although several other desaturases are capable of accepting electrons from cytoplasmic cytochromes, mutating key residues in the b 5 domain of Δ6-desaturases renders the enzymes nonfunctional, hinting that this domain may serve additional roles in Δ6-desaturases. , …”