NRPS Protein MarQ Catalyzes Flexible Adenylation and Specific S-Methylation
NRPS Protein MarQ Catalyzes Flexible Adenylation and Specific S-Methylation
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NRPS 蛋白 MarQ 催化灵活的腺苷酸化和特异性 S-甲基化
DOI：
10.1021/acschembio.8b00364
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发表时间：
2018-09-01
影响因子：
4
通讯作者：
Lin, Shuangjun
中科院分区：
文献类型：
--
作者：
Huang, Tingting;Duan, Yingyi;Lin, Shuangjun
Maremycins 是一组结构多样的 2,5-二酮哌嗪天然产物，具有稀有氨基酸结构单元 S-甲基-L-半胱氨酸 (Me-Cys)。提出了来自马雷霉素生物合成途径的三种独立非核糖体肽合成酶 (NRPS) 蛋白用于形成 2,5-二酮哌嗪支架：MarQ MarM 和 MarJ。 MarQ 对 Cys、Me-Cys、Ser 和 (S)-2,3-二氨基丙酸 (DAP) 显示灵活的腺苷酸化活性，并将这些底物转移至 MarJ，即离散肽基载体蛋白 (PCP)。 MarQ 还可以激活其他几种氨基酸。 MarQ 中嵌入的甲基转移酶 (MT) 结构域特异性催化 MarJ 束缚的 Cys 的硫醇甲基化。 MarQ和MarJ的体外重建进一步为Cys甲基化步骤的反应顺序提供了明确的证据。我们对 MarJ/Q 三域盒的研究获得了对马雷霉素结构多样性的宝贵见解，并将用于通过组合生物合成将 Me-Cys 纳入天然产物中。
Maremycins are a group of structurally diverse 2,5-diketopiperazine natural products featuring a rare amino acid building block, S-methyl-L-cysteine (Me-Cys). Three freestanding nonribosomal peptide synthetase (NRPS) proteins from the maremycins biosynthetic pathway were proposed for the formation of the 2,5-diketopiperazine scaffold: MarQ MarM, and MarJ. MarQ displays flexible adenylation activity toward Cys, Me-Cys, Ser, and (S)-2,3-diaminopropanoic acid (DAP) and transfers these substrates to MarJ, which is the discrete peptidyl carrier protein (PCP). MarQ could also activate several other amino acids. The embedded methyltransferase (MT) domain in MarQ specifically catalyzes the thiol methylation of MarJ-tethered Cys. The in vitro reconstitution of MarQ and MarJ further provides clear evidence for the reaction sequence of methylation step on Cys. Our study on MarJ/Q tridomain cassette gains valuable insights into maremycins structure diversity and will be exploited to incorporate Me-Cys into natural products by combinatorial biosynthesis.