生物发光是由域交替机制预测的被捕捉的火虫 luciferase 构造产生的
Bruce R Branchini1, Justin C Rosenberg, Danielle M Fontaine
1Department of Chemistry, Connecticut College, New London, Connecticut 06320, USA. brbra@conncoll.edu
Journal of the American Chemical Society
|June 29, 2011
概括
火虫光酶被设计成捕捉一个关键的C域旋转形状. 这种形状,类似于乙-CoA合成酶,允许生物发光,但阻止了露西芬氨基化,揭示了机械洞察力.
科学领域:
- 生物化学 生物化学
- 酶学 是一种酶学.
- 结构生物学 结构生物学
背景情况:
- 乙-A合成酶和甲虫光酶是基酶的子组,可催化不同的半反应.
- 酶功能的调节往往是由结构变化,特别是域旋转.
- 了解这些构造状态对于阐明酶机制至关重要.
研究的目的:
- 为了研究在火虫光酶中捕获特定的C域旋转形状的功能后果.
- 为了将 luciferase 的被困构造与 acyl-CoA 合成酶的构造进行比较.
- 探索这些酶超级家族中的腺化和氧化半反应之间的机制关系.
主要方法:
- 局部定向的突变发生,在火虫光酶的108和447位引入囊类残留物.
- 内部分子交叉链接使用1,2-bis(maleimido) 乙来捕获酶构成.
- 酶活性测定测量 luciferin adenylation 和生物发光与合成 luciferyl adenylate.
主要成果:
- 一种火 luciferase 变体成功交叉链接,将其困在一个新的 C 域旋转形状中.
- 交联 luciferase 丧失了腺化 luciferin 的能力.
- 交叉链路的光酶保留了几乎完全的生物发光活性,当提供合成光烯酸酸时.
结论:
- 捕获的形状类似于在化形成期间的乙烯基-CoA合成酶.
- 这表明,在相关的酶超级家族中,存在着涉及不同催化步骤的保存性构造状态.
- 该研究提供了结构和功能证据,通过域动态将腺化和氧化半反应联系起来.
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