Rendulić Toni, Mendonça Bahia Frederico, Soares-Silva Isabel, Nevoigt Elke, Casal Margarida
Centre of Molecular and Environmental Biology (CBMA), Department of Biology, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal.
Institute of Science and Innovation for Bio-Sustainability (IB-S), University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal.
J Fungi (Basel). 2022 Aug 6;8(8):822. doi: 10.3390/jof8080822.
Membrane transporters are important targets in metabolic engineering to establish and improve the production of chemicals such as succinic acid from renewable resources by microbial cell factories. We recently provided a strain able to strongly overproduce succinic acid from glycerol and CO in which the Dct-02 transporter from , assumed to be an anion channel, was used to export succinic acid from the cells. In a different study, we reported a new group of succinic acid transporters from the AceTr family, which were also described as anion channels. Here, we expressed these transporters in a succinic acid overproducing strain and compared their impact on extracellular succinic acid accumulation with that of the Dct-02 transporter. The results show that the tested transporters of the AceTr family hinder succinic acid accumulation in the extracellular medium at low pH, which is in strong contrast to Dct-02. Data suggests that the AceTr transporters prefer monovalent succinate, whereas Dct-02 prefers divalent succinate anions. In addition, the results provided deeper insights into the characteristics of Dct-02, showing its ability to act as a succinic acid importer (thus being bidirectional) and verifying its capability of exporting malate.
膜转运蛋白是代谢工程中的重要靶点，可用于通过微生物细胞工厂从可再生资源中建立和提高琥珀酸等化学品的产量。我们最近提供了一种能够从甘油和一氧化碳中大量过量生产琥珀酸的菌株，其中来自[具体来源]的Dct-02转运蛋白（假定为阴离子通道）被用于将琥珀酸从细胞中输出。在另一项研究中，我们报道了一组来自AceTr家族的新型琥珀酸转运蛋白，它们也被描述为阴离子通道。在此，我们在琥珀酸过量生产菌株中表达了这些转运蛋白，并将它们对细胞外琥珀酸积累的影响与Dct-02转运蛋白的影响进行了比较。结果表明，AceTr家族中经过测试的转运蛋白在低pH值下会阻碍细胞外培养基中琥珀酸的积累，这与Dct-02形成了强烈对比。数据表明，AceTr转运蛋白更喜欢单价琥珀酸盐，而Dct-02更喜欢二价琥珀酸阴离子。此外，这些结果更深入地揭示了Dct-02的特性，表明它能够作为琥珀酸的进口蛋白（因此具有双向性），并证实了它输出苹果酸的能力。
