通过氨基酸tRNA结合酶进行非核糖体延伸
Zhengan Zhang1, Wilfred A van der Donk1,2
1Department of Chemistry , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States.
Journal of the American Chemical Society
|November 22, 2019
概括
这项研究揭示了氨基酸tRNA连接酶 (PEARL) 如何将氨基酸添加到基架上. 我们展示了ATP直接化,阐明了天然产品的新生物合成机制.
科学领域:
- 生物化学
- 分子生物学
- 自然产品的生物合成
背景情况:
- 一种新的生物合成策略利用基架来合成天然产品.
- 氨基酸tRNA连接酶 (PEARL) 通过依赖ATP和tRNA的机制将氨基酸添加到C末端.
- 精确的PEARL催化氨基酸添加机制尚不清楚.
研究的目的:
- 在生物化学和机械学上描述TglB,来自*Pseudomonas syringae*的珍珠.
- 阐明TglB催化 (Cys) 加入TglA架的机制.
- 了解天然产品3-酸盐的生物合成.
主要方法:
- 使用TglB和TglA的酶动力学和基质特异性测定.
- 在TglB中保存残留物的位点定向突变发生.
- 使用截断的tRNA变体进行tRNACys识别的分析.
- 用于跟踪ATP利用的同位素标记研究.
主要成果:
- TglB可以识别TglA的C端附近的特定残留物,但可以容忍终端氨基酸的变化.
- TglB有效地识别包含受体干的截断tRNACys分子.
- 突变酶在TglB中发现了关键的催化残留物,并排除了乒乓球机制.
- 同位素标记证实ATP直接化TglA的C端碳酸盐.
结论:
- 该研究支持PEARL催化氨基酸添加中的ATP的直接酸化机制.
- 这项工作为参与自然产品生物合成的这种类型的酶提供了一般的机制模型.
- 了解这种途径对于设计新型氨基酸衍生天然产品至关重要.
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