通过 RecBCD 酶的 RecB 核酶域进行转补,揭示了在 χ 识别时对 RecA 负载的新见解
Theetha L Pavankumar1,2, C Jason Wong1,2, Yun Ka Wong1,2
1Department of Microbiology and Molecular Genetics, University of California, Davis, CA 95616, USA.
Nucleic acids research
|January 23, 2024
概括
通过RecBCD介导的同源重组需要RecA加载到ssDNA上. RecBCD经历了一个chi诱导的重新排列,而不是链接器介导的摇摆,以暴露其ReCA加载表面.
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:
- 同源重组是一种关键的DNA修复途径.
- RecBCD酶复合体在启动同源重组中起着至关重要的作用.
- 在单链DNA (ssDNA) 上加载RecA是RecBCD介导的关键步骤.
研究的目的:
- 调查 RecBCD 通过 RecBCD 在 ssDNA 上加载 RecA 的机制.
- 为了测试RecB核酶域 (RecBn) 在chi识别时通过链接器摆动出来的假设.
- 确定 RecBn 是否需要连接到 RecBCD 来加载 RecA.
主要方法:
- RecBCD-RecBn复合物的生物化学复合.
- 在RECA负载的体外功能测试.
- 在体内功能测试. in vivo功能测试.
主要成果:
- 一个重组复合的截断 RecBCD 和 RecBn 是功能性的.
- 即使在与RecBCD共价切断时,RecBn也保留了RecA加载活动.
- RecBn 不需要通过链接器连接到 RecBCD 来加载 RecA.
结论:
- RecBCD不依赖RecBn通过链接器进行摆动.
- RecBCD经历了一种Chi诱导的分子内部重新排列,以暴露ReCA加载表面.
- 这种重新排列对于招募和将ReCA加载到ssDNA至关重要.
相关概念视频
Conservative Site-specific Recombination and Phase Variation
6.0K
Because the DNA segments are cut and reorganized in a direction-specific manner, site-specific recombination has emerged as an efficient genetic engineering technique. Flippase and Cyclization recombinases or Flp and Cre, respectively, are two members of the tyrosine recombinase family derived from bacteriophages, that are used to mediate site-specific DNA insertions, deletions, and targeted expression of proteins in mammalian cell lines.
The recognition sites for Cre recombinase called LoxP...
The recognition sites for Cre recombinase called LoxP...
6.0K
The Replisome
33.5K
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 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...
33.5K
Homologous Recombination
50.5K
The basic reaction of homologous recombination (HR) involves two chromatids that contain DNA sequences sharing a significant stretch of identity. One of these sequences uses a strand from another as a template to synthesize DNA in an enzyme-catalyzed reaction. The final product is a novel amalgamation of the two substrates. To ensure an accurate recombination of sequences, HR is restricted to the S and G2 phases of the cell cycle. At these stages, the DNA has been replicated already and the...
50.5K
Crossing Over
4.4K
Crossing over is the exchange of genetic information between homologous chromosomes during prophase I of meiosis I. Genetic recombination gives rise to allelic diversity in the newly formed daughter cells. In humans, crossing over produces genetically distinct haploid egg and sperm cells that undergo fertilization to produce unique offspring. Before cell division starts, the germ cell’s chromosome(s) undergo duplication in the S phase of the cell cycle. As the cells enter prophase I,...
4.4K
Directing Proteins to the Rough Endoplasmic Reticulum
7.3K
The organelle-specific signaling sequences direct proteins synthesized in the cytosol to their final destination like ER, mitochondria, peroxisomes, etc. Some of the proteins directed to ER are then trafficked via vesicles to other organelles within the cell or the extracellular environment through the Golgi complex. For example, the rough ER synthesizes soluble proteins for transportation to the lysosomes or secretion out of the cell. It can also synthesize transmembrane proteins that can...
7.3K
Restarting Stalled Replication Forks
5.8K
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,...
5.8K


