通过高速原子力显微镜可视化氨聚合物的单分子酶延长
Toshiaki Mori1, Atsushi Hirose, Tatsuya Hagiwara
1Department of Biomolecular Engineering, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8501, Japan. tmori@bio.titech.ac.jp
Journal of the American Chemical Society
|November 28, 2012
概括
研究人员使用高速原子力显微镜观察了Pasteurella multocida氨酸合成酶 (pmHAS) 通过单分子氨酸合成. 在或脂质双层上固定的pmHAS显示了1-10mer s(-1的催化速率,揭示了酶活性动态.
科学领域:
- 生物化学 生物化学
- 分子生物学分子生物学
- 显微镜的使用方法
背景情况:
- 氨酸 (HA) 是细胞外矩阵中的一个关键的糖氨酸甘氨酸.
- 在单分子水平上了解HA合成机制对于生物和治疗应用至关重要.
- 帕斯图雷拉多酸氨酸合成酶 (pmHAS) 是HA生产中的一个关键酶.
研究的目的:
- 直接可视化和量化pmHAS的单分子酶活性.
- 在不同的固定条件下确定pmHAS的催化延长速率常数 (k ((cat)) .
- 为了将单分子运动数据与散装溶液测量数据进行比较.
主要方法:
- 使用高速扫描原子力显微镜 (HS-AFM) 实时观察酶活性.
- 帕斯图雷拉多酸氨酸合成酶 (pmHAS) 在表面和脂质双层上被固定.
- 反应是通过添加UDP-葡萄糖酸和UDP-N-乙糖胺单体来启动的.
主要成果:
- 在10秒间隔观察到单分子氨酸聚合物链的延长.
- 在上固定的pmHAS的平均 k ((cat) 为1.8 mer s ((-1).
- 集成到脂质双层的pmHAS显示保留活性,k ((cat) 值在1-10 mer s ((-1) (平均2-4 mer s ((-1)) 之间.
结论:
- 通过pmHAS,HS-AFM提供了单分子氨酸合成的直接可视化.
- 在脂质双层上酶固定保持高的催化活性,与相比或超过.
- 观察到的单分子动力学为HA合成机制和酶效率提供了洞察力.
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