在 Vitro 中对R-和S-β2氧酸的协同翻译性纳入:对E. E. 的结构和生物化学研究. 大肠杆菌的核糖体
Chandrima Majumdar1, Alexandra D Kent2, Noah X Hamlish1
1Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, California 94720, United States.
Journal of the American Chemical Society
|February 27, 2026
概括
研究人员设计了翻译系统,将修改后的氨基酸纳入其中,从而创造出新的生物聚合物. 低温EM显示,虽然两种形式的β-基氨酸都适合于核糖体,但细胞过程限制了体内结合,这是通过改进的酶系统克服的障碍.
科学领域:
- 生物化学 生物化学
- 分子生物学分子生物学
- 合成生物学 合成生物学
背景情况:
- 翻译装置的工程允许编程合成具有可调节性质的序列定义生物聚合物.
- β-酸对于合成生物相容聚合物和与天然产品类似的脱类具有兴趣.
- 之前的研究表明,β-基氨酸的两个反体都是M. alvi pyrrolysyl-tRNA合成酶/tRNA对的体外基质,但只有一个反体在体内被纳入.
研究的目的:
- 确定一种β-基氨酸反体在体内优先结合的结构基础.
- 调查核糖体步骤在限制两种反反体体体内结合中的作用.
- 使用工程化氨基酸-tRNA合成酶/tRNA对来证明两种酶体在体内有效的结合.
主要方法:
- 高分辨率低温电子显微镜 (cryo-EM) 用于确定结构.
- 使用乙基化tRNA的体外翻译反应.
- 质谱学和发光学用于量化翻译产品.
- 用工程直角氨基-tRNA合成酶/tRNA对进行细胞实验.
主要成果:
- 低温-EM结构显示, (R) - 和 (S) -β-基-氨酸异构体均在核糖体A位点处于同等位置.
- 在体外翻译反应中,对于两个反体,翻译产品的量大致相同.
- 实验表明,前核糖体细胞阶段,而不是核糖体本身,导致一种反体在体内优先结合.
- 一个工程直角氨基-tRNA合成酶/tRNA对促进了高产率,高保真度的体内结合两个反体.
结论:
- 核糖体可以容纳beta-hydroxy-lysine的两个反体,但细胞因素限制了体内结合.
- 在体内结合这两种反反体的首要障碍在于,在 ribozomal 酸键形成之前的步骤.
- 工程直角氨基-tRNA合成酶/tRNA对可以克服这些细胞的局限性,使蛋白质的高效和忠实生物合成与两个反体.
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