一种氨基酸tRNA合成酶,其序列不适合两个已知的类别中的任何一个
C Fàbrega1, M A Farrow, B Mukhopadhyay
1The Skaggs Institute for Chemical Biology, The Scripps Research Institute, Beckman Center, 10550 North Torrey Pines Road, La Jolla, California 92037, USA.
Nature
|May 3, 2001
概括
研究人员在古生物中发现了一种新的cysteinyl转移RNA合成酶,挑战了现有的蛋白质合成模型. 这种古老的酶缺乏正规的动机,这表明基本的氨基化反应具有不同的进化路径.
科学领域:
- 生物化学 生物化学
- 分子生物学分子生物学
- 进化生物学 进化生物学
背景情况:
- 氨基酸转移RNA合成酶是蛋白质合成的必需酶,催化氨基酸与相应的tRNA的附着.
- 这些酶根据活性位点结构和保存的序列动图被分为两种保存类.
- 一些古生物中缺乏可识别的cysteinyl-tRNA合成酶基因,这给理解蛋白质合成带来了难题.
研究的目的:
- 识别和描述古生物中的cysteinyl-tRNA合成酶,特别是Methanococcus jannaschii.
- 为了研究这种潜在的新型合成酶的进化起源和功能性质.
- 解决缺少正规合成酶基因的古生物中氨酸被纳入tRNA的机制.
主要方法:
- 生物信息分析以确定潜在的合成酶基因.
- 在体外生化测试以表征酶活性和基质特异性.
- 在古老的宿主体内进行体内研究,以确认功能.
主要成果:
- 在Methanococcus jannaschii和Deinococcus radiodurans中发现了一种新的cysteinyl-tRNA合成酶.
- 这种酶缺乏两种已知的tRNA合成酶类的特征,即保存的序列动图.
- 鉴定证实了它在体外和体内都能够将氨基酸氨基酸氨基酸对其同源tRNA的能力.
- 该酶的独特结构表明其起源很古,早于正规合成酶类的分歧.
结论:
- 这种独特的cysteinyl-tRNA合成酶的发现为蛋白质合成的演变提供了新的视角.
- 它挑战了在这些古生物中囊氨基化依赖于修饰的正规酶的概念.
- 这一发现表明,对于必不可少的氨基酸-tRNA合成酶,存在了替代的进化途径.
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