Interdisciplinary Centre of Marine and Environmental Research (CIIMAR/CIMAR), University of Porto, Avenida General Norton de Matos, s/n, 4450-208 Matosinhos, Portugal.
Department of Biology, Faculty of Sciences, University of Porto Rua do Campo Alegre, 4169-007 Porto, Portugal.
J Nat Prod. 2022 Jul 22;85(7):1704-1714. doi: 10.1021/acs.jnatprod.2c00162. Epub 2022 Jul 6.
Certain cyanobacteria of the secondary metabolite-rich order Nostocales can establish permanent symbioses with a large number of cycads, by accumulating in their coralloid roots and shifting their metabolism to dinitrogen fixation. Here, we report the discovery of two new lipoglycopeptides, desmamides A () and B (), together with their aglycone desmamide C (), from the nostocalean cyanobacterium LEGE 12446 isolated from a cycad () coralloid root. The chemical structures of the compounds were elucidated using a combination of 1D and 2D NMR spectroscopy and mass spectrometry. The desmamides are decapeptides featuring -glycosylation of tyrosine (in and ) and an unusual 3,5-dihydroxy-2-methyldecanoic acid residue. The biosynthesis of the desmamides was studied by substrate incubation experiments and bioinformatics. We describe herein the biosynthetic gene cluster and propose it to be associated with desmamide production. The discovery of this class of very abundant (>1.5% d.w.) bacterial lipoglycopeptides paves the way for exploration of their potential role in root endosymbiosis.
某些富含次生代谢产物的蓝细菌门念珠藻目蓝细菌可以与大量苏铁属植物建立永久性共生关系，通过在珊瑚状根中积累并将其代谢转变为固氮作用。在这里，我们报告了从苏铁珊瑚状根中分离出的念珠藻目蓝细菌 LEGE 12446 中发现的两种新的糖脂肽，desmamides A () 和 B ()，以及它们的糖苷配基 desmamide C ()。通过使用 1D 和 2D NMR 光谱和质谱联用技术，确定了化合物的化学结构。这些 desmamides 是由酪氨酸（在 和 中）和一种不寻常的 3,5-二羟基-2-甲基癸酸残基进行 -糖苷化的十肽。通过底物孵育实验和生物信息学研究了 desmamides 的生物合成。我们在此描述了该生物合成基因簇，并提出它与 desmamide 的产生有关。这类非常丰富（>1.5%干重）的细菌糖脂肽的发现为探索它们在根内共生中的潜在作用铺平了道路。
