Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School , 240 Longwood Avenue, Boston, Massachusetts 02115, United States.
Department of Bacteriology, University of Wisconsin-Madison , 1550 Linden Drive, Madison, Wisconsin 53706, United States.
J Am Chem Soc. 2017 Sep 20;139(37):12899-12902. doi: 10.1021/jacs.7b06176. Epub 2017 Sep 6.
Fungus-growing ants engage in complex symbiotic relationships with their fungal crop, specialized fungal pathogens, and bacteria that provide chemical defenses. In an effort to understand the evolutionary origins of this multilateral system, we investigated bacteria isolated from fungi. One bacterial strain (Streptomyces sp. CLI2509) from the bracket fungus Hymenochaete rubiginosa, produced an unusual peptide, tryptorubin A, which contains heteroaromatic links between side chains that give it a rigid polycyclic globular structure. The three-dimensional structure was determined by NMR and MS, including a C-C COSY of isotopically enriched material, degradation, derivatives, and computer modeling. Whole genome sequencing identified a likely pair of biosynthetic genes responsible for tryptorubin A's linear hexapeptide backbone. The genome also revealed the close relationship between CLI2509 and Streptomyces sp. SPB78, which was previously implicated in an insect-bacterium symbiosis.
与真菌作物、专门的真菌病原体以及提供化学防御的细菌共生的真菌养殖蚂蚁，建立了复杂的共生关系。为了了解这种多边系统的进化起源，我们研究了从真菌中分离出的细菌。从栓菌科的红栓菌中分离到的一种细菌菌株（链霉菌 CLI2509），产生了一种不寻常的肽，即 tryptorubin A，其侧链之间含有杂芳族键，赋予其刚性的多环球形结构。通过 NMR 和 MS 确定了其三维结构，包括对同位素标记材料进行 C-C COSY、降解、衍生物和计算机建模。全基因组测序鉴定了一对可能的生物合成基因，它们负责 tryptorubin A 的线性六肽骨架。该基因组还揭示了 CLI2509 与链霉菌 SPB78 之间的密切关系，此前 SPB78 与昆虫-细菌共生有关。
