通过C类激素S-adenosylmethionine甲基酶进行催化的结构和光谱基础,涉及诺西/诺卡生物合成
bioRxiv : the preprint server for biology
|February 6, 2026
概括
一个激进的S-adenosylmethionine甲基酶的第一个结构揭示了NocN如何在抗生素 nosiheptide 中安装一个独特的侧环. 这种机制涉及激素中间体和用于抗生素生物合成的特定催化残留物.
科学领域:
- 生物化学 生物化学
- 结构生物学 结构生物学
- 自然产品生物合成 自然产品生物合成
背景情况:
- 诺西 (NOS) 是一种强大的抗生素,属于核糖体合成和翻译后修饰 (RiPP) 类.
- NOS具有复杂的宏循环结构,含有提亚,脱水残留物,以及由3甲基-2-印酸 (MIA) 桥形成的独特侧环.
- MIA侧环的安装是由C级激素S-adenosylmethionine (SAM) 甲基酶,No.N.催化.
研究的目的:
- 确定NocN的X射线晶体结构,NosN的同类物,提供了对C类激素SAM甲基酶的第一个结构洞察力.
- 阐明NocN在noisheptide生物合成中催化MIA侧环的形成的机制.
主要方法:
- 采用X射线晶体学,获得NocN的高分辨率结构与结合的SAM分子以及产品模仿.
- 电子偏磁共振 (EPR) 光谱法被用来检测激素中间体在酶反应期间.
主要成果:
- 这些结构揭示了两个结合的SAM分子,其中一个定位用于从基质中抽取原子.
- 确定了一个关键的催化残留物Tyr276,结构表明SAM表皮化在激素生成中的作用.
- EPR光谱证实了基因物种的形成,这与将SAM衍生的甲基因添加到MIA基质相一致.
结论:
- 该研究提供了前所未有的结构和机制细节的C类激进SAM甲基酶.
- 这些发现揭示了抗生素noziheptide的生物合成,并为理解由激进SAM酶催化的其他RiPP修饰提供了基础.
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