Scholarlink

<p>6-thioguanine (6-TG) is a therapeutic medication for childhood acute lymphoblastic leukemia (ALL) and a potent antimicrobial agent. Its biosynthesis relies on the YcfA-YcfC system, yet the formation of its critical thioamide moiety remains incompletely understood. Here, we provide a detailed biochemical and structural characterization of YcfA, including apo and substrate-bound crystal structures, which reveal that substrate adenylation and L-cysteine addition are key initial steps in the reaction cascade. Cryo-electron microscopy (cryo-EM) and functional analyses highlight YcfA’s assembly into a two-layered heptameric structure, essential for the enzymatic function. GTP serves a dual role as a substrate and oligomerization enhancer. Additionally, pyridoxal 5’-phosphate (PLP), a cofactor for YcfC, the partner enzyme in this system, promotes YcfA oligomerization but inhibits its activity by obstructing GTP binding. Biochemical and structural evidence confirms that YcfC acts as a C‒S lyase, which is essential for thioamide formation in the presence of PLP. Exploiting substrate flexibility, we synthesized a seleno analog with antimicrobial properties. Multi-omics analyses of the biosynthetic precursor underscore its potential as an antibiotic. Collectively, our findings unravel the distinct architecture and functionality of the YcfA-YcfC system, offering an evolutionary perspective on noncanonical thioamide biosynthesis and a foundation for synthetic biology applications in drug development.</p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

The mechanism of thioamide formation by the YcfA-YcfC system in 6-thioguanine biosynthesis

  • 期刊论文

  • 出版模式：

    开放获取

  • 发表日期：

    2025年10月3日

查看全文
  • Li Zhang,
  • Chao Dou,
  • Weizhu Yan,
  • Pengpeng Chen,
  • Xinyu Jia,
  • Na Zhang,
  • Dan Zhou,
  • Zhaolin Long,
  • Lu Zhang,
  • Xiaofeng Zhu,
  • Wei Cheng

摘要

6-thioguanine (6-TG) is a therapeutic medication for childhood acute lymphoblastic leukemia (ALL) and a potent antimicrobial agent. Its biosynthesis relies on the YcfA-YcfC system, yet the formation of its critical thioamide moiety remains incompletely understood. Here, we provide a detailed biochemical and structural characterization of YcfA, including apo and substrate-bound crystal structures, which reveal that substrate adenylation and L-cysteine addition are key initial steps in the reaction cascade. Cryo-electron microscopy (cryo-EM) and functional analyses highlight YcfA’s assembly into a two-layered heptameric structure, essential for the enzymatic function. GTP serves a dual role as a substrate and oligomerization enhancer. Additionally, pyridoxal 5’-phosphate (PLP), a cofactor for YcfC, the partner enzyme in this system, promotes YcfA oligomerization but inhibits its activity by obstructing GTP binding. Biochemical and structural evidence confirms that YcfC acts as a C‒S lyase, which is essential for thioamide formation in the presence of PLP. Exploiting substrate flexibility, we synthesized a seleno analog with antimicrobial properties. Multi-omics analyses of the biosynthetic precursor underscore its potential as an antibiotic. Collectively, our findings unravel the distinct architecture and functionality of the YcfA-YcfC system, offering an evolutionary perspective on noncanonical thioamide biosynthesis and a foundation for synthetic biology applications in drug development.