Department of Bioengineering and Bioinformatics , Lomonosov Moscow State University , Moscow , 119992 , Russia.
Center for Data-Intensive Biomedicine and Biotechnology , Skolkovo Institute of Science and Technology , Skolkovo , 143025 , Russia.
J Am Chem Soc. 2018 Apr 25;140(16):5625-5633. doi: 10.1021/jacs.8b02277. Epub 2018 Apr 11.
Klebsazolicin (KLB) is a recently discovered Klebsiella pneumonia peptide antibiotic targeting the exit tunnel of bacterial ribosome. KLB contains an N-terminal amidine ring and four azole heterocycles installed into a ribosomally synthesized precursor by dedicated maturation machinery. Using an in vitro system for KLB production, we show that the YcaO-domain KlpD maturation enzyme is a bifunctional cyclodehydratase required for the formation of both the core heterocycles and the N-terminal amidine ring. We further demonstrate that the amidine ring is formed concomitantly with proteolytic cleavage of azole-containing pro-KLB by a cellular protease TldD/E. Members of the YcaO family are diverse enzymes known to activate peptide carbonyls during natural product biosynthesis leading to the formation of azoline, macroamidine, and thioamide moieties. The ability of KlpD to simultaneously perform two distinct types of modifications is unprecedented for known YcaO proteins. The versatility of KlpD opens up possibilities for rational introduction of modifications into various peptide backbones.
克拉西菌素（KLB）是一种最近发现的靶向细菌核糖体出口通道的肺炎克雷伯氏菌肽类抗生素。KLB 含有一个 N 端脒环和四个唑杂环，由专门的成熟机制插入核糖体合成的前体中。利用 KLB 生产的体外系统，我们表明 YcaO 结构域 KlpD 成熟酶是一种双功能环脱水酶，对于形成核心杂环和 N 端脒环都是必需的。我们进一步证明，酰胺环是通过细胞蛋白酶 TldD/E 对含唑的原 KLB 的蛋白水解切割同时形成的。YcaO 家族的成员是在天然产物生物合成中已知的激活肽羰基的多样化酶，导致唑啉、大脒和硫代酰胺部分的形成。KlpD 同时进行两种不同类型修饰的能力对于已知的 YcaO 蛋白来说是前所未有的。KlpD 的多功能性为各种肽骨架的合理引入修饰开辟了可能性。
