Gao Yaojie, Xu Gudan, Wu Pan, Liu Jin, Cai You-Sheng, Deng Zixin, Chen Wenqing
Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, and School of Pharmaceutical Sciences, Wuhan University, Wuhan, China.
Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, and School of Pharmaceutical Sciences, Wuhan University, Wuhan, China
Appl Environ Microbiol. 2017 May 1;83(10). doi: 10.1128/AEM.00078-17. Print 2017 May 15.
2'-Chloropentostatin (2'-Cl PTN, 2'-chloro-2'-deoxycoformycin) and 2'-amino-2'-deoxyadenosine (2'-amino dA) are two adenosine-derived nucleoside antibiotics coproduced by sp. strain ATCC 39365. 2'-Cl PTN is a potent adenosine deaminase (ADA) inhibitor featuring an intriguing 1,3-diazepine ring, as well as a chlorination at C-2' of ribose, and 2'-amino dA is an adenosine analog showing bioactivity against RNA-type virus infection. However, the biosynthetic logic of them has remained poorly understood. Here, we report the identification of a single gene cluster () essential for the biosynthesis of 2'-Cl PTN and 2'-amino dA. Further systematic genetic investigations suggest that 2'-Cl PTN and 2'-amino dA are biosynthesized by independent pathways. Moreover, we provide evidence that a predicted cation/H antiporter, AdaE, is involved in the chlorination step during 2'-Cl PTN biosynthesis. Notably, we demonstrate that 2'-amino dA biosynthesis is initiated by a Nudix hydrolase, AdaJ, catalyzing the hydrolysis of ATP. Finally, we reveal that the host ADA (designated ADA1), capable of converting adenosine/2'-amino dA to inosine/2'-amino dI, is not very sensitive to the powerful ADA inhibitor pentostatin. These findings provide a basis for the further rational pathway engineering of 2'-Cl PTN and 2'-amino dA production. 2'-Cl PTN/PTN and 2'-amino dA have captivated the great interests of scientists, owing to their unusual chemical structures and remarkable bioactivities. However, the precise logic for their biosynthesis has been elusive for decades. Actually, the identification and elucidation of their biosynthetic pathways not only enrich the biochemical repertoire of novel enzymatic reactions but may also lay solid foundations for the pathway engineering and combinatorial biosynthesis of this family of purine nucleoside antibiotics to generate novel hybrid analogs with improved features.
2'-氯喷司他丁（2'-Cl PTN，2'-氯-2'-脱氧助间型霉素）和2'-氨基-2'-脱氧腺苷（2'-氨基dA）是由sp.菌株ATCC 39365共同产生的两种腺苷衍生的核苷类抗生素。2'-Cl PTN是一种有效的腺苷脱氨酶（ADA）抑制剂，具有引人注目的1,3-二氮杂环庚烷环，以及核糖C-2'处的氯化，而2'-氨基dA是一种腺苷类似物，对RNA型病毒感染具有生物活性。然而，它们的生物合成逻辑仍知之甚少。在此，我们报告了对2'-Cl PTN和2'-氨基dA生物合成至关重要的单个基因簇（）的鉴定。进一步的系统遗传学研究表明，2'-Cl PTN和2'-氨基dA是通过独立途径生物合成的。此外，我们提供证据表明预测的阳离子/H反向转运蛋白AdaE参与了2'-Cl PTN生物合成过程中的氯化步骤。值得注意的是，我们证明2'-氨基dA生物合成由Nudix水解酶AdaJ催化ATP水解引发。最后，我们揭示宿主ADA（命名为ADA1）能够将腺苷/2'-氨基dA转化为肌苷/2'-氨基dI，对强大的ADA抑制剂喷司他丁不太敏感。这些发现为进一步合理改造2'-Cl PTN和2'-氨基dA的生产途径提供了基础。2'-Cl PTN/PTN和2'-氨基dA因其不寻常的化学结构和显著的生物活性而引起了科学家们极大的兴趣。然而，它们生物合成的确切逻辑几十年来一直难以捉摸。实际上，它们生物合成途径的鉴定和阐明不仅丰富了新型酶促反应的生化库，还可能为该嘌呤核苷类抗生素家族的途径工程和组合生物合成奠定坚实基础，以产生具有改进特性的新型杂合类似物。
