由Streptomyces antibioticus的脂酶C催化的酸丁醇的转循环
Chuan Bai1, Li Zhao, Mario Rebecchi
1Department of Medicinal Chemistry and Pharmacognosy, The University of Illinois at Chicago, Chicago, Illinois 60612, USA.
Journal of the American Chemical Society
|June 5, 2009
概括
来自Streptomyces antibioticus的依赖的酸氨基固醇特异脂酶C (saPLC1) 通过一种不寻常的1,6-循环化机制切割酸氨基. 这产生了内醇转-1,6-环酸盐,通过将酶产品与化学酶合成标准进行比较来证实.
科学领域:
- 生物化学 生物化学
- 酶学 是一种酶学.
- 微生物学 微生物学
背景情况:
- 酸丁氨基固醇特异性脂酶C (PLC) 酶在细胞信号传递中至关重要.
- PLC酶的催化机制通常涉及到伊诺醇cis-1,2-cyclic酸盐的形成.
- Streptomyces antibioticus phospholipase C 1 (saPLC1) 是一种依赖的酶,具有已知但尚未完全理解的催化机制.
研究的目的:
- 阐明由saPLC1.1进行的酸丁酸 (PI) 裂变的精确机制.
- 为了确定 saPLC1.1 产生的循环酸盐中间体的结构.
- 研究特定氨基酸残留在saPLC1.1的催化活性中的作用.
主要方法:
- 用于产生saPLC1.1的H16A突变体,使用了局部导向的突变发生.
- 分析了H16A突变体释放的循环酸盐产物.
- 通过化学酶方法合成了真正的内醇转-1,6-环酸 (1,6-IcP).
- 酶释放的循环酸盐与合成的1,6-IcP标准相比较.
主要成果:
- saPLC1的H16A突变释放了一个循环酸盐中间体.
- 对比显示,释放的中间体与化学酶合成的内醇转-1,6-循环酸盐 (1,6-IcP) 完全相同.
- 这表明saPLC1通过1,6-循环化途径催化PI裂变,与典型的1,2-循环化途径不同.
结论:
- saPLC1采用了一种不寻常的催化机制,涉及1,6-循环.
- 该酶产生伊诺西转-1,6-环酸盐 (1,6-IcP) 作为循环中间体.
- 这一发现挑战了对PLC酶机制的传统理解,并突出了这种酶类内的机制多样性.
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