Kong Dekun, Wang Xin, Liu Li
College of Pharmaceutical Sciences, Southwest University, Chongqing 400715, China.
Laboratory of Biochemistry and Molecular Biology, Lab Teaching and Management Center, Chongqing Medical University, Chongqing 400016, China.
J Fungi (Basel). 2025 Feb 20;11(3):171. doi: 10.3390/jof11030171.
The simplest cyclo-peptides, also known as diketopiperazines (DKPs), are widespread in nature. The growing interest in these simplest cyclo-peptides is driven by their significant potential for therapeutic applications. In this study, we identified a biosynthetic gene cluster from CRI323-04 through genome mining and heterologous expression in . The two core genes, and , within the gene cluster were characterized for their role in the biossoynthesis of aspkyncin, a novel DKP compound that incorporates a l-kynurenine (l-Kyn) unit. Furthermore, we successfully reconstituted the activities of the minimal bimodular non-ribosomal peptide synthetase (NRPS) AacA and the methyltransferase AacB both in vivo and in vitro. Our findings demonstrate that AacA catalyzes the condensation and cyclization of two non-proteinogenic amino acids, l-Kyn and -methyl-l-alanine, to produce aspkyncin without the involvement of any release domain. Notably, the -methyl-l-alanine is generated by a specialized l-alanine -methyltransferase AacB prior to NRP assembly. This study reveals an unconventional pathway for the biosynthesis of fungal DKPs.
最简单的环肽，也被称为二酮哌嗪（DKPs），在自然界中广泛存在。对这些最简单环肽的兴趣日益浓厚，是由它们在治疗应用方面的巨大潜力所驱动的。在本研究中，我们通过基因组挖掘和在……中的异源表达，从CRI323 - 04中鉴定出一个生物合成基因簇。该基因簇内的两个核心基因，……和……，因其在aspkyncin生物合成中的作用而得到表征，aspkyncin是一种新型的DKP化合物，包含一个L - 犬尿氨酸（L - Kyn）单元。此外，我们在体内和体外成功地重建了最小双模块非核糖体肽合成酶（NRPS）AacA和甲基转移酶AacB的活性。我们的研究结果表明，AacA催化两种非蛋白质ogenic氨基酸，L - Kyn和α - 甲基 - L - 丙氨酸的缩合和环化，以产生aspkyncin，而无需任何释放结构域的参与。值得注意的是，α - 甲基 - L - 丙氨酸是在NRP组装之前由一种特殊的L - 丙氨酸α - 甲基转移酶AacB产生的。这项研究揭示了真菌DKPs生物合成的一条非常规途径。
