在聚胺生物合成过程中,B12- SAM基酶PoyC催化瓦林Cβ-甲基化
Aubérie Parent1, Alain Guillot1, Alhosna Benjdia1
1Micalis Institute, ChemSyBio, INRA, AgroParisTech, Université Paris-Saclay , F-78350 Jouy-en-Josas, France.
Journal of the American Chemical Society
|December 10, 2016
概括
研究人员确定PoyC是第一个依赖于B12的激素S-腺胺酶,可以进行甲基化. 这一发现有助于了解聚氨胺生物合成和B12基的S-腺胺酶.
科学领域:
- 生物化学
- 分子生物学
- 自然产品合成
背景情况:
- 核糖体合成和转化后改性 (RiPPs) 是一种具有药用用途的多样化自然产品.
- 聚胺A是一种RiPP,具有独特的翻译后修饰,包括C-甲基化.
- 两个激进的S-adenosylmethionine (rSAM) 酶,PoyB和PoyC,被提议用于催化这些C-甲基化.
研究的目的:
- 为了研究假定的rSAM酶PoyC的体外活性.
- 要确定PoyC是否催化Cβ甲基化.
- 阐明RiPP生物合成中的B12依赖rSAM酶的机制.
主要方法:
- 使用PoyC进行体外酶测定.
- 反应产物的分析,包括S-adenosylhomocysteine和5'-deoxyadenosine.
- 酶内B12辅因子 (MeCbl) 的表征.
主要成果:
- PoyC被证实是第一个依赖于B12的rSAM酶催化Cβ甲基化.
- 该酶将甲基从S-adenosylmethionine转移到一个l-valine残留物.
- 鉴定出一种密集结合的甲基胺 (MeCbl) 辅因子,在催化过程中转移甲基.
结论:
- PoyC的活性为聚胺生物合成提供了新的见解.
- 这项研究揭示了B12-rSAM酶在修改核糖体中的关键作用.
- 这些发现扩大了已知的B12依赖酶及其催化机制.
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