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来自Streptomyces antibioticus的酸丁氨基醇特异性脂酶C的独特催化机制

Chuan Bai¹, Li Zhao, Ming-Daw Tsai

¹Department of Medicinal Chemistry and Pharmacognosy, The University of Illinois at Chicago, Chicago, Illinois 60612, USA.

Journal of the American Chemical Society

|January 8, 2010

概括

这项研究揭示了如何修改酸盐组的酸盐 (PI) 影响其通过Streptomyces抗生素酸酶C (saPLC1) 的分解. 在特定位置的硫替代大大改变了酶活性和反应机制.

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:

来自Streptomyces antibioticus的酸丁醇特异性酸酶C (saPLC1) 通过循环中间体将酸丁醇 (PI) 水解.
了解saPLC1的机制对于阐明脂质信号通路和酶动力学至关重要.

研究的目的:

研究PI的酸盐部分中硫替代对saPLC1的催化活性和机制的影响.
为了分析PI酸化酸盐和酸化酸盐类型的水解产物.

主要方法:

在非桥接 (pro-R,pro-S) 和桥接位置使用硫的PI类似物的合成和酶性水解.
动力分析以确定saPLC1的催化速率常数,使用修改PI基板.
产品分析,以确定PI类似物和循环中间体的水解产品.

主要成果:

用硫取代pro-S氧气大大降低了saPLC1活性 (3 x 10^7倍下降),而pro-R替代具有轻微的影响.
在S(p) 酸类型的桥梁位置引入第二个硫,显著增加了裂变速率 (2 x 10^5倍),表明转向解离机制.
1,6-伊诺西托循环酸盐 (1,6-IcP) 异构体的水解产生了不同的产物,而 trans-1,6-IcP 水解通过活性位点重定向产生伊诺西托6-酸.

结论:

在PI类似物中硫替代的立体化学有关重要影响saPLC1的催化速率和机制.
酸酸和酸酸类似物揭示了saPLC1的催化步骤的机制性见解.
酶活性部位的灵活性,通过转-1,6-IcP的重定向来证明,在产品形成中起着关键作用.

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