切换β-ketoacyl-acyl载体蛋白合成酶,FabH和BioZ的严格基质特异性
Xudong Hang1, Lin Zhang2, Yanqiang Huang3
1National Health Commission Key Laboratory of Tropical Disease Control, School of Tropical Medicine, Hainan Medical University, Haikou, Hainan 571199, China.
概括
研究人员通过改变一个小的蛋白质部分,在脂肪酸和生物合成酶FabH和BioZ之间交换了功能. 这揭示了酶基质特异性的关键结构决定因素.
科学领域:
- 酶学 是一种酶学.
- 结构生物学 结构生物学
- 代谢工程是代谢工程.
背景情况:
- β-基酸载体蛋白 (ACP) 合成酶是脂肪酸和生物生物合成中必不可少的酶.
- FabH (β-ketoacyl-ACP合成酶III) 和BioZ是具有明显基质特异性的同源酶:FabH使用乙-CoA,而BioZ使用谷氨酸-CoA.
- 这些不同的基质特异性的结构基础仍然不清楚.
研究的目的:
- 阐明FabH和BioZ中基质特异性的分子决定因素.
- 调查FabH和BioZ之间的功能互换性.
- 为潜在的治疗应用提供有关酶识别和催化物的见解.
主要方法:
- 将BioZ与谷氨酸-CoA联合结晶以获得结构数据.
- 通过将BioZ中的β8-α9循环和Ala317移植到FabH.
- 从FabH到BioZ的结构元素的逆接种.
- 酶活性测定用于评估基质特异性的变化.
主要成果:
- 确定了BioZ:glutaryl-CoA复合物的晶体结构.
- 将BioZ β8-α9循环和Ala317移植到大肠杆菌中,FabH成功地将其基质特异性从乙烯基-CoA转移到谷氨基-CoA.
- 反向修改BioZ赋予了类似于FabH的活性,证明了功能交换.
结论:
- β8-α9循环和残留物Ala317是FabH和BioZ中基质特异性的最小结构决定因素.
- 通过修改这些特定的结构元素,可以交换酶功能和基质偏好.
- 这些发现为了解酶机制和开发向抑制剂提供了基础.
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