在前蛋白转位酶的催化循环的不同步骤中,delta mu H+和ATP的功能不同
E Schiebel1, A J Driessen, F U Hartl
1Molecular Biology Institute, University of California, Los Angeles 90024-15.
Cell
|March 8, 1991
概括
在大肠杆菌中,前蛋白转位涉及Seca,ATP和膜潜力. 当SecA不受约束时,电化学潜力驱动转位,而当SecA受约束时,ATP驱动步骤移动.
科学领域:
- 细胞生物学 细胞生物学
- 生物化学 生物化学
- 分子生物学分子生物学
背景情况:
- 通过大肠杆菌的内膜进行前蛋白转移对于蛋白质分泌至关重要.
- 这个过程需要来自ATP水解和质子动力 (PMF) 的能量.
- 转位酶机制,包括SecA和SecYEG通道,调解这种转位.
研究的目的:
- 阐明ATP和膜电化学电位 (delta mu H+) 在前蛋白转位中的不同作用.
- 调查SeCA和delta mu H+合作或独立行动的机制.
主要方法:
- 在体外研究中,使用SecA,proOmpA和脂质体等纯化成分.
- 操纵ATP水平和膜潜力,观察转位的影响.
主要成果:
- 结合proOmpA和ATP的SecA启动了逐步转位,ATP水解释放了蛋白质.
- 膜电化学潜力 (delta mu H+) 驱动快速转位,当SecA不受约束时.
- delta mu H+驱动的转位被SecA和非水解ATP类似物抑制,这表明有不同的机制.
结论:
- 无论是依赖ATP的路径还是依赖delta mu H+的路径,都会对大肠杆菌中的前蛋白转位产生影响.
- 德尔塔H+提供了独立于SecA结合的快速转位机制,特别是在ATP或SecA可用性较低的条件下.
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