细胞DNA聚合酶过程性因子PCNA的晶体结构
T S Krishna1, X P Kong, S Gary
1Laboratories of Molecular BIophysics, Rockefeller University, New York, New York 10021.
Cell
|December 30, 1994
概括
增殖细胞核抗原 (PCNA) 的晶体结构是DNA复制中的关键蛋白质,揭示了围绕DNA的环状形成. 这种结构与细菌对应物相似,表明DNA复制中的保存机制.
科学领域:
- 分子生物学分子生物学
- 结构生物学 结构生物学
- 生物化学 生物化学
背景情况:
- 增殖细胞核抗原 (PCNA) 对于真核DNA复制至关重要,作为DNA聚合酶delta的过程性因子.
- 了解PCNA的结构对于阐明真核生物中DNA复制的机制至关重要.
研究的目的:
- 为了确定Saccharomyces cerevisiae PCNA的晶体结构.
- 了解PCNA如何与DNA相互作用并促进聚合酶活性.
主要方法:
- 使用X射线晶体学来确定S. cerevisiae PCNA的晶体结构.
- 该结构的分辨率为2.3 Å分辨率.
主要成果:
- 晶体结构显示PCNA形成了一个三元环,由每个单体组成的两个相同的域组成.
- PCNA环是一种封闭结构,其尺寸和静电性质适合围绕双重DNA.
- 在三元真核PCNA环和二元细菌PCNA环 (大肠杆菌DNA聚合酶III全酶的β子单元) 之间观察到一个惊人的结构相似性,尽管没有显著的序列相同性.
结论:
- PCNA环可能环绕着DNA,形成DNA聚合酶附着的平台.
- 真核和原核PCNA环之间的结构相似性支持DNA复制过程性的一种保存机制.
- 这一发现为真核生物和 prokaryotic DNA 复制之间的机械联系提供了结构性证据.
相关概念视频
Replication in Eukaryotes
Overview
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...
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...
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...
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...
Nucleic Acid Structure
The pentose sugar in DNA is deoxyribose, while in RNA the pentose sugar is ribose. The difference between the sugars is the presence of the hydroxyl group on the ribose's second carbon and a hydrogen on the deoxyribose's second carbon. The phosphate residue attaches to the hydroxyl group of the 5′ carbon of one sugar and the hydroxyl group of the 3′ carbon of the sugar of the next nucleotide, which forms a 5′ to 3′ phosphodiester linkage.
DNA Structure
DNA has a double-helix structure. The...
DNA Structure
DNA has a double-helix structure. The...


