十层 SelA•tRNA(Sec) 环结构揭示了细菌单半氨酸形成的机制
Yuzuru Itoh1, Markus J Bröcker, Shun-ichi Sekine
1RIKEN Systems and Structural Biology Center, Tsurumi, Yokohama 230-0045, Japan.
Science (New York, N.Y.)
|April 6, 2013
概括
细菌的单半氨酸 (Sec) 合成涉及SelaA酶,它形成一个环状结构,对功能至关重要. 这项研究揭示了SelaA.
科学领域:
- 生物化学 生物化学
- 分子生物学分子生物学
- 结构生物学 结构生物学
背景情况:
- 单半氨酸 (Sec) 是第21个氨基酸,通过翻译后合成.
- 对于Sec合成存在两个不同的途径:细菌 (SelA) 和古生物/真核生物 (SepSecS).
研究的目的:
- 通过SELA阐明细菌Sec合成的结构基础.
- 要了解tRNA的机制 ((Sec) 识别和Sec形成由SelaA.
主要方法:
- 艾奎菲克斯 (Aquifex aeolicus SelA) 复合物的X射线晶体学.
- 在体内和体外的酶测定.
主要成果:
- 确定了SelaA的晶体结构,揭示了结合10个tRNA(Sec) 分子的环状同体相.
- 确定了N端域在特定D臂结合和Ser-tRNA的歧视中的作用.
- 显示的脱化对于SelaA活性和氧醇5'-酸盐依赖的Sec形成至关重要.
结论:
- 细菌和古生物/真核生物的Sec合成途径是独立进化的,由不同的蛋白质结构和基质协调支持.
- 塞拉的独特结构促进了特定基质的结合和催化,突出显示了进化差异.
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