来自Archaea的一种非典型的topoisomerase II,对中介性重组有影响
A Bergerat1, B de Massy, D Gadelle
1Institut de Génétique et Microbiologie, Université Paris Sud, CNRS URA 1354, Orsay, France.
Nature
|March 27, 1997
概括
科学家在Sulfolobus shibatae中发现了一种新型的拓酶II酶,与已知的家族不同. 这一发现揭示了对DNA拓调节和DNA修复机制的新见解.
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:
- 二型拓酶通过DNA链转移和短暂的双链断裂来调节DNA拓.
- 所有先前确定的II型拓酶都属于单一的蛋白质家族.
研究的目的:
- 克隆和测序来自古人群Sulfolobus shibatae的拓酶II的基因.
- 要描述这种酶,并确定其与已知的II型多酶的关系.
- 为了研究同源蛋白的功能,如Saccharomyces cerevisiae Spo11,在DNA过程中.
主要方法:
- 基因克隆和对Sulfolobus shibatae topoisomerase II子单元的基因测序.
- 序列相似性分析,将新型酶与已知的拓酶和其他蛋白质家族 (Hsp90,MutL) 进行比较.
- 在Saccharomyces cerevisiae Spo11蛋白中保存的氨酸的局部定向突变发生.
主要成果:
- 苏尔福洛布斯 (Sulfolobus shibatae topoisomerase II) 是一个新家族,与其他II型酶的相似性有限,除了B子单元中保留的ATP结合基因.
- 该A子单元与功能不明的蛋白质有相似之处,包括Spo11,这对介质重组启动至关重要.
- 突变酶证实Spo11中保存的氨酸对其活性至关重要.
结论:
- 硫杆菌Shibatae酶是新型II型多聚酶家族的第一个成员.
- 保存的图案表明不同蛋白质家族的ATP结合和水解有共同的机制.
- Spo11可能作为II型拓酶起作用,催化双链断裂,从而在S. cerevisiae中启动介质重组.
更多相关视频
07:55Detection of Homologous Recombination Intermediates via Proximity Ligation and Quantitative PCR in Saccharomyces cerevisiae
Published on: September 11, 2022
10:13Simple and Fast Rolling Circle Amplification-Based Detection of Topoisomerase 1 Activity in Crude Biological Samples
Published on: December 2, 2022
相关概念视频
DNA Topoisomerases
Topoisomerases are enzymes that relax overwound DNA molecules during various cell processes, including DNA replication and transcription. These enzymes regulate positive and negative DNA supercoiling without changing the nucleotide sequence. DNA overwinding in a clockwise direction results in positively supercoiled DNA, whereas underwinding in a counterclockwise direction produces negatively supercoiled DNA.
Types and Mechanism of action
Topoisomerases are divided into two main types. Type I...
Types and Mechanism of action
Topoisomerases are divided into two main types. Type I...
Homologous Recombination
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...
Conservative Site-specific Recombination and Phase Variation
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...
Homologous Recombination
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...
Crossing Over
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, duplicated...
Diversity of Archaea III
Crenarchaeota, a prominent phylum of Archaea, is remarkable for its ability to thrive in extreme environments characterized by high temperatures and acidity. These microorganisms inhabit sulfuric hot springs, volcanic systems, and submarine hydrothermal vents, where temperatures often exceed 100°C. The unique adaptations of Crenarchaeota not only allow survival under such extreme conditions but also provide insights into the mechanisms of life in primordial Earth-like environments.Morphological...
