Proliferating Cell Nuclear Antigen Uses Two Distinct Modes to Move along DNA
Proliferating Cell Nuclear Antigen Uses Two Distinct Modes to Move along DNA
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DOI：
10.1074/jbc.m109.008706
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发表时间：
2009-06-26
影响因子：
4.8
通讯作者：
van Oijen, Antoine M.
中科院分区：
文献类型：
--
作者：
Kochaniak, Anna B.;Habuchi, Satoshi;van Oijen, Antoine M.
增殖细胞核抗原（PCNA）通过与DNA拓扑结合，募集复制和修复蛋白，在真核生物基因组的维持中起重要作用。环状蛋白质在双链DNA周围形成一个封闭的环，并且能够以随机行走的方式沿着DNA沿着移动。这种扩散过程的分子性质知之甚少。我们使用单分子成像技术来观察单个荧光标记的PCNA分子沿着伸展的DNA的运动。作为粘度和蛋白质大小的函数的扩散特性的测量表明，PCNA沿着DNA移动使用两种不同的滑动模式。大多数情况下，夹具移动，同时旋转地跟踪DNA双链体的螺距。在不太常用的第二种扩散模式中，蛋白质的运动与螺距分离，并且夹钳以高得多的速率扩散。
Proliferating cell nuclear antigen (PCNA) plays an important role in eukaryotic genomic maintenance by topologically binding DNA and recruiting replication and repair proteins. The ring-shaped protein forms a closed circle around double-stranded DNA and is able to move along the DNA in a random walk. The molecular nature of this diffusion process is poorly understood. We use single-molecule imaging to visualize the movement of individual, fluorescently labeled PCNA molecules along stretched DNA. Measurements of diffusional properties as a function of viscosity and protein size suggest that PCNA moves along DNA using two different sliding modes. Most of the time, the clamp moves while rotationally tracking the helical pitch of the DNA duplex. In a less frequently used second mode of diffusion, the movement of the protein is uncoupled from the helical pitch, and the clamp diffuses at much higher rates.