L-histidine调节HD3脱氧核糖酶的催化活性和形状变化
Nae Sakimoto1, Hirofumi Imanaka2, Elisa Tomita-Sudo1
1Konan Laboratory for Oligonucleotide Therapeutics (KOLOT), 7-1-20 Minatojima-minamimachi, Chuo-ku, Kobe 650-0047, Hyogo, Japan.
Genes
|November 27, 2024
概括
L-histidine对于HD3脱氧酶的功能和结构至关重要. 这种分子驱动着催化活动和适当的折叠,正如实验中一致的结合常数所示.
科学领域:
- 生物化学 生化学
- 分子生物学分子生物学
- 核酸化学的核酸化学
背景情况:
- рибо开关是调节性核酸,通过小分子结合来控制基因表达.
- 脱氧核糖酶是具有催化功能的人工核酸,通过体外选择开发出来.
- 一种依赖于l-histidine的脱氧酶先前显示了RNA裂变活性,模仿了核糖酶机制.
研究的目的:
- 阐明l-histidine在l-histidine依赖脱氧酶 (HD) 衍生物的催化活性和结构形成中的作用,HD3.
- 为了研究HD3对l-histidine的反应中的结合特性和形状变化.
- 使用各种分析技术量化l-histidine与HD3的结合亲和力.
主要方法:
- 循环二重化 (CD) 光谱法用于监测HD3的形状变化,在不同的l-histidine度下.
- 用碳-14 (14C) 标记的l-histidine和液体闪计数用于直接结合分析.
- 酶动力学测试测量HD3的催化活性在一系列的l-histidine度.
主要成果:
- 由l-histidine引起的形状变化 (Ka(CD)) 的结合常数被确定为2.0 × 10^3 M^-1.
- 发现催化活性 (Ka(Rxn)) 和直接结合 (Ka(RI)) 的结合常量大约为1.0 × 10^3 M^-1.
- 在CD,催化活性和结合试验中一致的结合常量表明l-histidine的重要作用.
结论:
- 对于HD3脱氧酶的催化功能和结构完整性来说,L-histidine是必不可少的.
- 结合l-histidine会诱导HD3活性所需的特定形状变化.
- 这些数据强烈支持l-histidine在这种脱氧酶的活性折叠和催化机制中的关键作用.
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