National Center for Biotechnology, Life Science & Environment Research Institute, King Abdulaziz City for Science and Technology, Riyadh 11442, Saudi Arabia.
Molecules. 2022 Jul 13;27(14):4473. doi: 10.3390/molecules27144473.
Polyesters containing 2,4-dihydroxy-6-(2-hydroxypropyl)benzoate and 3-hydroxybutyrate moieties have been isolated from many fungal species. was previously reported to produce a similar polyester, talapolyester G. The complete genome sequence and the development of bioinformatics tools have enabled the discovery of the biosynthetic potential of this microorganism. Here, a putative biosynthetic gene cluster (BGC) of the polyesters encoding a highly reducing polyketide synthase (HR-PKS) and nonreducing polyketide synthase (NR-PKS), a cytochrome P450 and a regulator, was identified. Although talapolyester G does not require an oxidative step for its biosynthesis, further investigation into the secondary metabolite production of resulted in isolating two new metabolites called talarodioxadione and talarooxime, in addition to three known compounds, namely 6-hydroxymellein, 15G256α and transtorine that have never been reported from this organism. Interestingly, the biosynthesis of the cyclic polyester 15G256α requires hydroxylation of an inactive methyl group and thus could be a product of the identified gene cluster. The two compounds, talarooxime and transtorine, are probably the catabolic metabolites of tryptophan through the kynurenine pathway. Tryptophan metabolism exists in almost all organisms and has been of interest to many researchers. The biosynthesis of the new oxime is proposed to involve two subsequent N-hydroxylation of 2-aminoacetophenone.
已从许多真菌物种中分离出含有 2,4-二羟基-6-(2-羟丙基)苯甲酸酯和 3-羟基丁酸酯部分的聚酯。 先前曾报道过产生类似聚酯的 talapolyester G。完整的基因组序列和生物信息学工具的发展使我们能够发现这种微生物的生物合成潜力。在这里，鉴定了聚酯的假定生物合成基因簇 (BGC)，其编码高度还原的聚酮合酶 (HR-PKS) 和非还原的聚酮合酶 (NR-PKS)、细胞色素 P450 和调节剂。尽管 talapolyester G 的生物合成不需要氧化步骤，但对 的次生代谢产物生产的进一步研究导致分离出两种新的代谢产物，称为 talarodioxadione 和 talarooxime，以及三种从未从该生物中报道过的已知化合物，即 6-羟甲麦角因、15G256α 和 transtorine。有趣的是，环状聚酯 15G256α 的生物合成需要对一个非活性甲基进行羟化，因此可能是鉴定出的基因簇的产物。两种化合物，talarooxime 和 transtorine，可能是色氨酸通过犬尿氨酸途径的分解代谢产物。色氨酸代谢存在于几乎所有生物体中，一直受到许多研究人员的关注。新肟的生物合成提议涉及 2-氨基苯乙酮的两个随后的 N-羟化。
