Key Laboratory of Marine Drugs, Ministry of Education of China, School of Medicine and Pharmacy, Ocean University of China, 266003, Qingdao, China.
Laboratory for Marine Drugs and Bioproducts of Qingdao National Laboratory for Marine Science and Technology, 266003, Qingdao, China.
Nat Commun. 2018 Oct 5;9(1):4091. doi: 10.1038/s41467-018-06411-x.
Cyclodipeptide synthases (CDPSs) can catalyze the formation of two successive peptide bonds by hijacking aminoacyl-tRNAs from the ribosomal machinery resulting in diketopiperazines (DKPs). Here, three CDPS-containing loci (dmt1-3) are discovered by genome mining and comparative genome analysis of Streptomyces strains. Among them, CDPS DmtB1, encoded by the gene of dmt1 locus, can synthesize cyclo(L-Trp-L-Xaa) (with Xaa being Val, Pro, Leu, Ile, or Ala). Systematic mutagenesis experiments demonstrate the importance of the residues constituting substrate-binding pocket P1 for the incorporation of the second aa-tRNA in DmtB1. Characterization of dmt1-3 unravels that CDPS-dependent machinery is involved in CDPS-synthesized DKP formation followed by tailoring steps of prenylation and cyclization to afford terpenylated DKP compounds drimentines. A phytoene-synthase-like family prenyltransferase (DmtC1) and a membrane terpene cyclase (DmtA1) are required for drimentines biosynthesis. These results set the foundation for further increasing the natural diversity of complex DKP derivatives.
环二肽合酶（CDPSs）可以通过劫持核糖体机制中的氨酰-tRNA 来催化两个连续肽键的形成，从而产生二酮哌嗪（DKPs）。在这里，通过对链霉菌菌株的基因组挖掘和比较基因组分析，发现了三个含有 CDPS 的基因座（dmt1-3）。其中，由 dmt1 基因座编码的 CDPS DmtB1 可以合成环（L-Trp-L-Xaa）（其中 Xaa 为 Val、Pro、Leu、Ile 或 Ala）。系统的诱变实验表明，构成底物结合口袋 P1 的残基对于 DmtB1 中第二个 aa-tRNA 的掺入非常重要。对 dmt1-3 的研究揭示，CDPS 依赖性机制参与了由 CDPS 合成的 DKP 形成，随后进行 prenylation 和环化的修饰步骤，以产生萜烯化的 DKP 化合物 drimentines。需要一种类 phytoene-synthase 家族 prenyltransferase（DmtC1）和一种膜萜烯环化酶（DmtA1）来合成 drimentines。这些结果为进一步增加复杂 DKP 衍生物的天然多样性奠定了基础。
