通过启动循环和差异合成速率协调DNA复制
Manjula Pandey1, Salman Syed, Ilker Donmez
1Department of Biochemistry, University of Medicine and Dentistry of New Jersey-Robert Wood Johnson Medical School, Piscataway, New Jersey 08854, USA.
Nature
|November 20, 2009
概括
通过协调的机制,DNA复制实现了相同的链合成速率. 在DNA合成过程中制造出RNA原始酶,形成一个循环,确保高效的聚合酶交换和更快的滞后链合成.
科学领域:
- 分子生物学分子生物学
- 遗传学 是一个遗传学.
- 生物化学 生物化学
背景情况:
- DNA复制需要协调合成领先和滞后的链.
- 滞后链通过Okazaki碎片不连续地合成,这对同等的合成速度构成了挑战.
研究的目的:
- 阐明协调机制,确保在复制过程中确保相同的DNA链合成速率.
- 研究T7复制蛋白在协调领先和滞后链合成中的作用.
主要方法:
- 利用T7复制蛋白来研究DNA合成动态.
- 实时观察到原料合成和聚合酶活性.
主要成果:
- 在正在进行的DNA合成过程中",随时"合成RNA原始体.
- 领先链聚合酶受到化酶速度的限制,而不是原料合成.
- 一个启动循环促进了酶-酶和复制复合体之间的连续接触.
- 滞后链聚合酶比领先链聚合酶更快地合成DNA.
结论:
- 三种协同作用的机制协调了DNA复制:同时发生的原料合成,一个原料循环以实现高效的传递,以及更快的滞后链聚合酶活性.
- 这些机制确保领先和落后链DNA合成的净速率相等.
- T7复合体协调DNA合成,在原始合成过程中不会暂停.
相关概念视频
The 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...
The 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...
Lagging 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...
DNA Replication
DNA replication involves the separation of the two strands of the double helix, with each strand serving as a template from which the new complementary strand is copied. After replication, each double-stranded DNA includes one parental or “old” strand and one “new” strand. This is known as semiconservative replication. The resulting DNA molecules have the same sequence and are divided equally into the two daughter cells.
Replication in Prokaryotes
DNA replication uses a large number of...
Replication in Prokaryotes
DNA replication uses a large number of...
Restarting 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...
Translesion DNA Polymerases
Translesion (TLS) polymerases rescue stalled DNA polymerases at sites of damaged bases by replacing the replicative polymerase and installing a nucleotide across the damaged site. Doing so, TLS allows additional time for the cell to repair the damage before resuming regular DNA replication.
TLS polymerases are found in all three domains of life - archaea, bacteria, and eukaryotes. Of the different classes of TLS polymerases, members of the Y family are fitted with specialized structures that...
TLS polymerases are found in all three domains of life - archaea, bacteria, and eukaryotes. Of the different classes of TLS polymerases, members of the Y family are fitted with specialized structures that...


