Thuringiensin is a thermostable nucleoside metabolite produced by Bacillus thuringiensis and has insecticidal activity against various pests. The synthesis cluster of thuringiensin was cloned and the biosynthesis pathway deduced and clarified in a previous study. ThuE catalyzes phosphorylation from precursor C to thuringiensin in the final step of thuringiensin maturation. However, the transport mechanism of thuringiensin remains unclear. Here, we identify a novel predicted MFS transporter named ThuT (thuringiensin transporter) which is necessary for the biosynthesis and secretion of thuringiensin. A thuT gene deletion resulted in a massive loss of thuringiensin in the extracellular space and a small accumulation in the intracellular space, implying its role in the transport of thuringiensin. The overall abundance of thuringiensin was significantly reduced, while the accumulation of precursor C in the thuT mutant suggests its role in thuringiensin biosynthesis. Further proteinprotein interaction analysis demonstrated that ThuT forms a complex with ThuE, which suggests the mechanism by which ThuT participates in thuringiensin maturation. We have identified the first transporter of thuringiensin and propose that the ThuT-ThuE complex could couple the maturation and transport of thuringiensin to avoid thuringiensin accumulation. A novel high-efficiency model coupling the synthesis and secretion of antibiotics has been revealed in B.thuringiensis.

Thuringiensin 是一种由Bacillus thuringiensis产生的耐热核苷代谢物，对多种害虫具有杀虫活性。克隆了苏云金素的合成簇，并在先前的研究中推导和阐明了生物合成途径。ThuE 在苏云金素成熟的最后一步催化从前体 C 到苏云金素的磷酸化。然而，苏云金素的转运机制仍不清楚。在这里，我们确定了一种名为 ThuT（苏云金素转运蛋白）的新型预测 MFS 转运蛋白，它是苏云金素生物合成和分泌所必需的。thuT基因缺失导致苏云金素在细胞外空间大量丢失，并在细胞内少量积累。细胞内空间，暗示其在苏云金素转运中的作用。苏云金素的总体丰度显着降低，而前体 C 在thuT突变体中的积累表明其在苏云金素生物合成中的作用。进一步的蛋白质蛋白质相互作用分析表明，ThuT 与 ThuE 形成复合物，这表明 ThuT 参与苏云金素成熟的机制。我们已经确定了苏云金素的第一个转运蛋白，并提出 ThuT-ThuE 复合物可以耦合苏云金素的成熟和转运以避免苏云金素的积累。在苏云金芽孢杆菌中揭示了一种耦合抗生素合成和分泌的新型高效模型。