细菌中TIM桶前转移酶的两个不同的机制
Emma H Doud1, Deborah L Perlstein, Manuel Wolpert
1Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02139, United States.
Journal of the American Chemical Society
|January 11, 2011
概括
两个细菌前转移酶 (PTs) 显示出不同的反应机制. MoeO5使用了前所未有的异构化途径,而PcrB是第一个在细菌中的酶,它先化了甘-1-酸盐 (G1P).
科学领域:
- 生物化学 生物化学
- 酶学 是一种酶学.
- 分子生物学分子生物学
背景情况:
- 甲基转移酶 (PTs) 是合成各种异oprenoid化合物的关键酶.
- 蒂姆桶是一个常见的结构图案,在许多酶中发现,包括PTs.
- 了解PT反应机制,可以了解新陈代谢途径和酶进化.
研究的目的:
- 研究两种细菌TIM桶前转移酶MoeO5和PcrB的反应机制.
- 阐明这些酶的基质特异性和催化途径.
- 为了比较TIM桶家族中不同PT使用的不同机制.
主要方法:
- 进行了酶动力学测试,以描述MoeO5和PcrB的活性.
- 使用质谱学和NMR光谱学的产品分析确定了反应中间体和产品.
- 使用局部定向突变发生来探测参与催化过程的关键残留物.
主要成果:
- MoeO5通过前所未有的异构化,催化了法纳西尔转移到3-糖酸 (3PG) 转移到尼罗利迪尔酸盐中间体.
- 鉴定PcrB是第一个用geranyl和geranylgeranyl组对糖醇-1-酸盐 (G1P) 进行prenylate的细菌酶.
- PcrB的反应机制涉及直接的prenyl转移而没有异构化,保留了prenyl捐赠体的跨基键.
结论:
- 细菌TIM桶前转移酶表现出显著的机理多样性.
- MoeO5 采用了一种新的反应途径来进行前转移,与以前已知的机制不同.
- 与MoeO5.5相比,PcrB扩大了细菌PTs已知的基质范围,并使用了与MoeO5.5相比不同的催化策略.
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