滞后链复制的解释:聚合酶在DNA滑动之间跳跃
P T Stukenberg1, J Turner, M O'Donnell
1Microbiology Department, Cornell University Medical College, New York, New York 10021.
Cell
|September 9, 1994
概括
DNA聚合酶III全酶通过部分分解和重新组装,快速合成奥卡扎基碎片. 这种新的机制允许酶在DNA模板和β之间有效循环.
科学领域:
- 分子生物学分子生物学
- 生物化学 生物化学
- 遗传学 是一个遗传学.
背景情况:
- DNA聚合酶III全酶,大肠杆菌中的复制酶,对于DNA复制至关重要.
- 这种酶通过环形β滑动固定在DNA上.
- 高效的DNA复制需要聚合酶反复结合和释放DNA,特别是在滞后链上的Okazaki片段合成.
研究的目的:
- 为了阐明DNA聚合酶III全酶在滞后链合成过程中启动和关闭DNA的机制.
- 了解聚合酶如何管理大量Okazaki碎片的合成快速周转.
主要方法:
- 这项研究可能涉及体外生化分析和潜在的结构生物学技术,以观察聚合酶--DNA相互作用.
- 分析多子单元DNA聚合酶III全酶的分解和重组过程.
主要成果:
- DNA聚合酶III全酶利用了一种新的机制,包括部分分解和随后重新组装,以在DNA模板之间过渡.
- 聚合酶在完成模板后从β脱离,脱离DNA,并与一个新的β结合在不同的原始位置.
- 在聚合酶解开后,β仍然与DNA结合,可能作为其他细胞机械的协调点.
结论:
- DNA聚合酶III全酶采用动态解离-重组策略,以实现高效的复制循环.
- 这种机制促进了Okazaki碎片在滞后链上的快速和持续的DNA合成.
- 在聚合酶释放后β的解离表明它在协调复制与其他DNA代谢过程中的作用.
相关概念视频
01:59Lagging Strand Synthesis
During replication, the complementary strands in double-stranded DNA are synthesized at different rates. Replication first begins on the leading strand. Replication starts later, occurs more slowly, and proceeds discontinuously on the lagging strand.
There are several major differences between synthesis of the leading strand and synthesis of the lagging strand. 1) Leading strand synthesis happens in the direction of replication fork opening, whereas lagging strand synthesis happens in the...
There are several major differences between synthesis of the leading strand and synthesis of the lagging strand. 1) Leading strand synthesis happens in the direction of replication fork opening, whereas lagging strand synthesis happens in the...
03:01The Replisome
DNA replication is carried out by a large complex of proteins that act in a coordinated matter to achieve high-fidelity DNA replication. Together this complex is known as the DNA replication machinery or the replisome.
The synthesis of the leading and lagging strands is a highly coordinated process. To explain this, the “Trombone model” was proposed by Bruce Alberts in 1980. The DNA loop formation starts when a primer is synthesized on the parent lagging strand. The loop grows with the...
The synthesis of the leading and lagging strands is a highly coordinated process. To explain this, the “Trombone model” was proposed by Bruce Alberts in 1980. The DNA loop formation starts when a primer is synthesized on the parent lagging strand. The loop grows with the...
02:37Restarting Stalled Replication Forks
DNA replication is initiated at sites containing predefined DNA sequences known as origins of replication. DNA is unwound at these sites by the minichromosome maintenance (MCM) helicase and other factors such as Cdc45 and the associated GINS complex.The unwound single strands are protected by replication protein A (RPA) until DNA polymerase starts synthesizing DNA at the 5’ end of the strand in the same direction as the replication fork. To prevent the replication fork from falling apart, a...
01:59Lagging Strand Synthesis
During replication, the complementary strands in double-stranded DNA are synthesized at different rates. Replication first begins on the leading strand. Replication starts later, occurs more slowly, and proceeds discontinuously on the lagging strand.
There are several major differences between synthesis of the leading strand and synthesis of the lagging strand. 1) Leading strand synthesis happens in the direction of replication fork opening, whereas lagging strand synthesis happens in the...
There are several major differences between synthesis of the leading strand and synthesis of the lagging strand. 1) Leading strand synthesis happens in the direction of replication fork opening, whereas lagging strand synthesis happens in the...
03:01The Replisome
DNA replication is carried out by a large complex of proteins that act in a coordinated matter to achieve high-fidelity DNA replication. Together this complex is known as the DNA replication machinery or the replisome.
The synthesis of the leading and lagging strands is a highly coordinated process. To explain this, the “Trombone model” was proposed by Bruce Alberts in 1980. The DNA loop formation starts when a primer is synthesized on the parent lagging strand. The loop grows with the...
The synthesis of the leading and lagging strands is a highly coordinated process. To explain this, the “Trombone model” was proposed by Bruce Alberts in 1980. The DNA loop formation starts when a primer is synthesized on the parent lagging strand. The loop grows with the...
02:37Restarting Stalled Replication Forks
DNA replication is initiated at sites containing predefined DNA sequences known as origins of replication. DNA is unwound at these sites by the minichromosome maintenance (MCM) helicase and other factors such as Cdc45 and the associated GINS complex.The unwound single strands are protected by replication protein A (RPA) until DNA polymerase starts synthesizing DNA at the 5’ end of the strand in the same direction as the replication fork. To prevent the replication fork from falling apart, a...