揭示了婴儿隔离物Bifidobacterium breve的GH42β-银酸酶的转银化开关 DSM20213
Konlarat Phirom-On1,2, Khanh-Trang Vu-Le1,3, Leander Sützl1
1Food Biotechnology Laboratory, Institute of Food Technology, Department of Biotechnology and Food Science, BOKU University, Muthgasse 18, A-1190 Vienna, Austria.
概括
研究人员通过修改关键酶β-galactosidase (Bbreβgal-III) 来增强银河酸-寡糖 (GOS) 的产生. 突变Arg121显著提高了GOS产量和改变了产品成分,为预微生物合成提供了对酶工程的见解.
科学领域:
- 酶学 是一种酶学.
- 生物化学 生物化学
- 微生物学 微生物学
背景情况:
- β-Galactosidases 对于从乳糖中合成益生菌银-寡糖糖 (GOS) 至关重要,这对婴儿营养很重要.
- 来自*Bifidobacterium breve*的β-galactosidase Bbreβgal-III表现出较低的转银化活性,有利于水解并产生特定的GOS链接.
研究的目的:
- 为了研究保存的Arg121残留物和活动地点水道在Bbreβgal-III的催化活性中的作用.
- 通过理性突变和水道工程来增强转银酸酶活性并改变GOS产品配置.
主要方法:
- 对Bbreβgal-III进行结构分析,以了解其活跃地点和水道.
- 在Arg121残留物中的位点和突变发生.
- 活动地点水道的氨酸扫描.
- 通过转黄糖化反应分析GOS产量和产品成分.
主要成果:
- 与催化Glu160相邻的Arg121残留物在引导Bbreβgal-III向水解方面发挥着至关重要的作用.
- 121的突变性,特别是R121C变体,显著增加了GOS产量 (34%对17%野生类型),并改变了产品的特异性.
- 通过氨酸扫描设计水道也增强了转银酸酶活性,表明了水分子运动的重要性.
结论:
- 在GH42β-galactosidases中,Arg121充当了在水解和转酸酶化活动之间切换的关键决定因素.
- 修改活动现场残留物和水道可访问性为优化GOS生产提供了可行的策略.
- 这项研究为工程β-galactosidases提供了有价值的结构-功能见解,以增强益生菌合成.
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