由OxyB催化的氧化烯合反应:来自万科米辛生产生物体的细胞染色体P450. 对万科米辛生物合成的影响
Katharina Woithe1, Nina Geib, Katja Zerbe
1Department of Chemistry, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland.
Journal of the American Chemical Society
|May 5, 2007
概括
细胞染色体P450酶OxyB促进了万科米辛抗生素合成中的初始合. 这项研究证明了OxyB.
科学领域:
- 生物化学 生物化学
- 分子生物学分子生物学
- 酶学 是一种酶学.
背景情况:
- 类似万科米辛的糖抗生素是由复杂的非核糖体合成酶 (NRPS) 机制合成的.
- 细胞染色体P450酶,如OxyB,在生物合成期间催化关键反应中起着至关重要的作用.
- 最初的联反应是一个关键的步骤,通常发生在与载体蛋白 (PCP) 域连接的介质上.
研究的目的:
- 为了研究OxyB酶的基质特异性和催化活性.
- 阐明OxyB在万科米辛生物合成过程中介质的交叉链接中的作用.
- 为了确定OxyB与模型基质的动力参数和结合特性.
主要方法:
- 使用了具有不同序列和长度的模型基质,连接到来自万科NRPS模块的重组载体蛋白 (PCP).
- 采用生物化学测试来监测由OxyB催化的联反应.
- 确定酶动力学 (kcat,Km) 和基质结合 (Kd) 使用诸如紫外线光谱等技术.
主要成果:
- OxyB催化了基基糖 (Hpg) 和氨酸残留在六和六-PCP结合物的交叉链接.
- 酶的活性取决于电子供应 (铁素,黄素减少酶) 和分子氧气.
- 动力分析显示模型基板的kcat为0.1s-1和Km在4-13μM范围内,平衡结合的Kd为17 ± 5μM.
结论:
- OxyB可以对不同的线性中间体起作用,这表明万科米辛生物合成途径的灵活性.
- 该酶能够在六和七基质上进行交叉链接,这突显了它在形成糖核结构方面的重要性.
- 了解OxyB的机制,可以了解复杂的糖抗生素的生物合成.
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