对模板张力对T7DNA聚合酶活性影响的单分子研究
G J Wuite1, S B Smith, M Young
1Department of Physics, University of California, Berkeley 94720, USA.
Nature
|March 15, 2000
概括
T7 DNA聚合酶作为一个分子电机,在DNA复制过程中产生机械力. 这种力有助于组织模板基,并且可以在张力下增加核酸去除活性.
科学领域:
- 分子生物学分子生物学
- 生物物理学的生物物理.
背景情况:
- T7 DNA聚合酶快速复制DNA (100+个基数/秒),具有3'到5'外核酶活性.
- 酶的"右手"结构 (手指,手掌,指) 是聚合酶的典型特征.
- 复制的速度限制步骤涉及开放和关闭状态之间的构造变化.
研究的目的:
- 为了研究DNA复制过程中T7DNA聚合酶产生的机械力.
- 量化酶在压力下作为分子电机的功能能力.
主要方法:
- 利用单分子测试利用单链和双链DNA的不同弹性.
- 在DNA聚合的速度限制步骤中产生的测量机械力.
主要成果:
- T7 DNA聚合酶产生机械力,能够承受高达34 pN的模板张力.
- 酶在每一个催化周期中组织两个模板基,执行重要的机械和性工作.
- 在超过40 pN的力下,外核酶活动增加了100倍.
结论:
- T7DNA聚合酶作为一个分子电机,将化学能量转化为机械力.
- 力量生成是酶的催化循环和基组织的组成部分.
- 高机械力可以调节酶的外核酶活性.
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