人类端粒四重复体的热展开过程中的拥挤中间体
Robert D Gray1, Robert Buscaglia, Jonathan B Chaires
1James Graham Brown Cancer Center, University of Louisville, Louisville, Kentucky 40202, USA.
Journal of the American Chemical Society
|September 20, 2012
概括
人类端粒DNA的展开涉及复杂的中间结构. 光谱分析显示,在Tel22的热变质过程中,在61°C的温度下,可能存在三环螺旋中间体,这为G-四环稳定性提供了洞察力.
科学领域:
- 生物化学 生物化学
- 分子生物学分子生物学
- 生物物理学的生物物理.
背景情况:
- 人类端粒对于保持染色体稳定性至关重要.
- 端粒DNA可以形成G-四重复结构,影响其功能.
- 了解端粒DNA变性是理解其生物学作用的关键.
研究的目的:
- 为了研究人类端粒DNA序列的热变性简介.
- 识别和描述DNA展开过程中形成的中间结构.
- 为了确定这些中间体的热力学参数和光谱特性.
主要方法:
- 循环二重化 (CD) 光谱法用于监测结构变化.
- 光光谱学使用腺因 → 2 - 氨基氨酸类似物.
- 光共振能量转移 (FRET) 以追踪在特定地点的展开.
- 单值分解 (SVD) 和非线性最小平方适用于数据分析.
主要成果:
- Tel22 DNA 展开最好通过一个有两个中间体的顺序路径来建模.
- 在61°C观察到的一种高化的中间体 (I(2) 呈现出明显的CD光谱特征.
- 光数据表明,在中间状态下溶剂暴露增加.
- 61°C中间体的光谱特性与三重螺旋结构一致.
结论:
- 人类端粒DNA (Tel22) 的展开通过中间状态进行.
- 一个潜在的三螺旋结构被确定为一个重要的中间体.
- 这些发现增强了我们对G-quadruplex稳定性和动态的理解.
相关概念视频
02:41Telomeres and Telomerase
In eukaryotic DNA replication, a single-stranded DNA fragment remains at the end of a chromosome after the removal of the final primer. This section of DNA cannot be replicated in the same manner as the rest of the strand because there is no 3’ end to which the newly synthesized DNA can attach. This non-replicated fragment results in gradual loss of the chromosomal DNA during each cell duplication. Additionally, it can induce a DNA damage response by enzymes that recognize single-stranded DNA.
02:41Telomeres and Telomerase
In eukaryotic DNA replication, a single-stranded DNA fragment remains at the end of a chromosome after the removal of the final primer. This section of DNA cannot be replicated in the same manner as the rest of the strand because there is no 3’ end to which the newly synthesized DNA can attach. This non-replicated fragment results in gradual loss of the chromosomal DNA during each cell duplication. Additionally, it can induce a DNA damage response by enzymes that recognize single-stranded DNA.
01:29Replication in Eukaryotes
In eukaryotic cells, DNA replication is highly conserved and tightly regulated. Multiple linear chromosomes must be duplicated with high fidelity before cell division, so there are many proteins that fulfill specialized roles in the replication process. Replication occurs in three phases: initiation, elongation, and termination, and ends with two complete sets of chromosomes in the nucleus.
Many Proteins Orchestrate Replication at the Origin
Eukaryotic replication follows many of the same...
Many Proteins Orchestrate Replication at the Origin
Eukaryotic replication follows many of the same...
02:31Replication in Eukaryotes
Overview
01:03Single-Strand DNA Binding Proteins
For successful DNA replication, the unwinding of double-stranded DNA must be accompanied by stabilization and protection of the separated single strands of the DNA. This crucial task is performed by single-strand DNA-binding (SSB) proteins. They bind to the DNA in a sequence-independent manner, which means that the nitrogenous bases of the DNA need not be present in a specific order for binding of SSB proteins to it. The binding of SSB proteins straightens single-stranded DNA (ssDNA) and makes...
02:31Homologous 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...