| Autor: |
Li D; Research School of Chemistry, The Australian National University, Canberra, ACT 2601, Australia., Damry AM; Research School of Chemistry, The Australian National University, Canberra, ACT 2601, Australia., Petrie JR; CSIRO Agriculture Flagship, Black Mountain Laboratories, Canberra, ACT 2601, Australia., Vanhercke T; CSIRO Agriculture Flagship, Black Mountain Laboratories, Canberra, ACT 2601, Australia., Singh SP; CSIRO Agriculture Flagship, Black Mountain Laboratories, Canberra, ACT 2601, Australia., Jackson CJ; Research School of Chemistry, The Australian National University, Canberra, ACT 2601, Australia.; ARC Centre of Excellence in Synthetic Biology, Macquarie University, 19 Eastern Road, North Ryde, Sydney, NSW 2109, Australia. |
| Abstrakt: |
Marine algae are a major source of ω-3 long-chain polyunsaturated fatty acids (ω3-LCPUFAs), which are conditionally essential nutrients in humans and a target for industrial production. The biosynthesis of these molecules in marine algae requires the desaturation of fatty acids by Δ6-desaturases, and enzymes from different species display a range of specificities toward ω3- and ω6-LCPUFA precursors. In the absence of a molecular structure, the structural basis for the variable substrate specificity of Δ6-desaturases is poorly understood. Here we have conducted a consensus mutagenesis and ancestral protein reconstruction-based analysis of the Δ6-desaturase family, focusing on the ω3-specific Δ6-desaturase from Micromonas pusilla (MpΔ6des) and the bispecific (ω3/ω6) Δ6-desaturase from Ostreococcus tauri (OtΔ6des). Our characterization of consensus amino acid substitutions in MpΔ6des revealed that residues in diverse regions of the protein, such as the N-terminal cytochrome b 5 domain, can make important contributions to determining substrate specificity. Ancestral protein reconstruction also suggests that some extant Δ6-desaturases, such as OtΔ6des, could have adapted to different environmental conditions by losing specificity for ω3-LCPUFAs. This data set provides a map of regions within Δ6-desaturases that contribute to substrate specificity and could facilitate future attempts to engineer these proteins for use in biotechnology. |
