Zhang Yalong, Wu Lin, Wang Zuwei, Han Wenyu, Kerr Tyler A, Tang Yi
J Am Chem Soc. 2025 Jun 4;147(22):18923-18933. doi: 10.1021/jacs.5c03321. Epub 2025 May 19.
Peptide natural products (PNPs) are important sources of bioactive compounds. Recent studies have shown that oligopeptides or pseudopeptides can be synthesized by amide-bond-forming enzymes such as ATP-grasp enzymes and amide-bond synthetases (ABSs). By focusing on ATP-grasp enzymes as part of a conserved biosynthetic enzyme ensemble, genome mining of PNPs was performed on three biosynthetic gene clusters (BGCs) from diverse fungi, including RS, the causative agent of valley fever. We demonstrate that the conserved enzymes synthesize a common dipeptide fragment, l-leucine-l--isoindolinone-homoserine (l-Leu-l-Isd), which is modified and diversified into three PNPs (-) by associated enzymes in the three pathways. Pathway reconstitution and enzymatic assays led to the characterization of six ATP-grasp enzymes and ABSs that catalyze di-, tri-, and tetrapeptide formation. From the BGC, a flavoenzyme catalyzing the direct oxidation of l-tryptophan to l-oxindolylalanine was discovered. Our work validates ATP-grasp enzymes and ABSs as leads to mine new PNPs and further showcases the biocatalytic potential of these enzymes in catalyzing amide-bond formation.
肽类天然产物（PNPs）是生物活性化合物的重要来源。最近的研究表明，寡肽或拟肽可以由诸如ATP抓握酶和酰胺键合成酶（ABSs）等形成酰胺键的酶合成。通过将ATP抓握酶作为保守生物合成酶系的一部分进行聚焦，对来自不同真菌的三个生物合成基因簇（BGCs）进行了PNPs的基因组挖掘，其中包括引起山谷热的病原体RS。我们证明，这些保守酶合成了一个共同的二肽片段，L-亮氨酸-L-异吲哚啉酮-高丝氨酸（L-Leu-L-Isd），该片段在三条途径中被相关酶修饰并多样化为三种PNPs（-）。途径重建和酶活性测定导致了六种催化二肽、三肽和四肽形成的ATP抓握酶和ABSs的表征。从该BGC中，发现了一种催化L-色氨酸直接氧化为L-羟吲哚基丙氨酸的黄素酶。我们的工作验证了ATP抓握酶和ABSs作为挖掘新PNPs的线索，并进一步展示了这些酶在催化酰胺键形成方面的生物催化潜力。
