Allemann Marco N, Shulse Christine N, Allen Eric E
Marine Biology Research Division, Scripps Institution of Oceanography, University of California, San Diego, La Jolla, CA, United States.
Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California, San Diego, La Jolla, CA, United States.
Front Microbiol. 2019 Apr 3;10:702. doi: 10.3389/fmicb.2019.00702. eCollection 2019.
Various marine gamma-proteobacteria produce omega-3 polyunsaturated fatty acids, such as eicosapentaenoic acid (20:5, EPA) and docosahexaenoic acid (22:6, DHA), which are incorporated into membrane phospholipids. Five genes, designated , encode the polyketide/fatty acid synthase necessary for production of these long-chain fatty acids. In addition to biosynthesis of EPA and DHA, the "Pfa synthase" is also involved with production of a long-chain polyunsaturated hydrocarbon product (31:9, PUHC) in conjunction with the hydrocarbon biosynthesis pathway. In this work, we demonstrate that OleA mediates the linkage between these two pathways . Co-expression of along with from in yielded the expected product, a 31:8 ketone along with a dramatic ∼10-fold reduction in EPA content. The decrease in EPA content was independent of 31:8 ketone production as co-expression of an OleA active site mutant also led to identical decreases in EPA content. We also demonstrate that a gene linked with either and/or operons in diverse bacterial lineages, herein designated , plays a role in maintaining optimal production of Pfa synthase derived products in and species.
多种海洋γ-变形菌会产生ω-3多不饱和脂肪酸，如二十碳五烯酸（20:5，EPA）和二十二碳六烯酸（22:6，DHA），这些脂肪酸会被整合到膜磷脂中。有五个基因，命名为 ，编码这些长链脂肪酸合成所需的聚酮/脂肪酸合酶。除了EPA和DHA的生物合成外，“Pfa合酶”还与长链多不饱和烃产物（31:9，PUHC）的产生有关，且与 烃生物合成途径相关。在这项研究中，我们证明OleA介导了这两条途径之间的联系。将 与来自 的 共表达于 中，产生了预期产物，即一种31:8酮，同时EPA含量显著降低了约10倍。EPA含量的降低与31:8酮的产生无关，因为OleA活性位点突变体的共表达也导致EPA含量出现相同程度的降低。我们还证明，在不同细菌谱系中与 和/或 操纵子相关的一个基因，在此命名为 ，在维持 和 物种中Pfa合酶衍生产物的最佳产量方面发挥作用。
