通过DNA Pol II对转化合成的结构洞察
1Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, 9000 Rockville Pike, Building 5, Room B1-03, Bethesda, MD 20892, USA.
Cell
|January 13, 2010
概括
大肠杆菌DNA聚合酶II (Pol II) 和真核生物Rev3是执行转化合成的B家族聚合酶. DNA Pol II利用独特的结构特征,包括模板跳转,绕过DNA病变并保持基因组完整性.
科学领域:
- 分子生物学分子生物学
- 生物化学 生物化学
- 结构生物学 结构生物学
- 遗传学 是一个遗传学.
背景情况:
- 包括大肠杆菌DNA Pol II和真核细胞Rev3在内的B家族聚合酶对于DNA修复至关重要.
- 高保真性复制聚合酶在复制经过受损或不匹配的DNA位点时可能无效.
- 转载合成 (TLS) 是一种由专门的聚合酶用来绕过DNA损伤的机制.
研究的目的:
- 阐明大肠杆菌DNA Pol II的生物化学和结构性质,使转化合成成为可能.
- 了解DNA Pol II绕过DNA损伤的机制,包括模板跳转.
- 为了研究DNA Pol II如何平衡无损DNA的高效复制与TLS能力.
主要方法:
- 生物化学分析以表征DNA Pol II活动.
- 结构研究以确定DNA Pol II的三维结构.
- 在活性和外核酶位点之间对DNA基质分割的分析.
主要成果:
- DNA Pol II可以直接或通过模板跳转扩展原始原料过去的病变,容纳在小腔中的循环外模板核酸.
- 能够容纳多个循环输出替代品的能力使绕道合成的突变光谱复杂化.
- 在活性位点和校对外核酶位点之间的DNA基质的改变分区增强了TLS.
- 微妙的氨基酸变化远离活性部位允许DNA Pol II有效地复制正常DNA,同时也执行TLS.
结论:
- DNA Pol II 具有独特的结构和生化特性,可促进高效的转化合成.
- 模板跳转和改变基质分区是使DNA Pol II能够绕过DNA损伤的关键机制.
- DNA Pol II 是一种特殊的B家族聚合酶,能够进行高可靠性复制和耐损伤.
相关概念视频
02:10Translesion 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...
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...
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...
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...
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...
02:40DNA 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...