细胞外G-四复合体和Z-DNA保护生物膜免受DNase I的影响,G-四复合体形成具有过氧化酶活性的DNA酶
Gabriel Antonio Salvador Minero1, Andreas Møllebjerg1, Celine Thiesen1
1Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Gustav Wieds Vej 14, 8000 Aarhus, Denmark.
Nucleic acids research
|January 31, 2024
概括
葡萄球菌生物膜含有Z-DNA和G-四重复结构,可以保护它们免受核酶的影响. 这些非正规的DNA形式也表现出过氧化酶活性,有助于生物膜防御.
科学领域:
- 微生物学 微生物学
- 结构生物学 结构生物学
- 生物化学 生物化学
背景情况:
- 细菌形成生物膜以保护,利用一个富含多糖,蛋白质和细胞外DNA (eDNA) 的细胞外基质.
- 生物膜中eDNA的精确结构形式和功能,特别是Z-DNA和G-quadruplexes等非正规DNA结构,仍然在很大程度上未被探索.
研究的目的:
- 为了研究在Staphylococcus epidermidis生物膜中非正规DNA结构 (Z-DNA,G-四重复) 的存在和功能.
- 确定这些结构是否有助于生物膜对核酶降解的保护.
- 探索eDNA在生物膜矩阵中的潜在酶活性.
主要方法:
- 培养的 Staphylococcus epidermidis 生物膜含有黑和 NaCl 来稳定 DNA 结构.
- 利用免疫标记和光显微镜可视化DNA结构.
- 在宏观生物膜成像中采用光学连贯性断层扫描.
- 开发了体外检测试验,以测试Z-DNA和G-四重复DNA寡头的核酶降解.
- 在小鼠植入物相关骨髓炎模型中证实了这些结构的存在.
主要成果:
- Z-DNA和G-quadruplex DNA在葡萄球菌生物膜矩阵中很丰富,经常形成类似网络的结构.
- 这些结构需要NaCl和机械应力才能形成,这表明eDNA和多糖之间的相互作用.
- 哺乳动物DNase I对Z-DNA和G-quadruplex DNA无效,而Micrococcal核酶和S1 Aspergillus核酶显示了特定的降解活动.
- 生物膜中的细胞外DNA,在黑的存在下,表现出具有过氧化酶样功能的DNA酶活性.
结论:
- 非正规的DNA结构,Z-DNA和G-四复合体,是葡萄球菌生物膜的组成部分,有助于结构完整性和保护.
- 特定的核酶,如 Staphylococcus aureus 中的微球菌核酶,可能在生物膜分散中发挥作用.
- 生物膜中的细胞外DNA具有内在的过氧化酶活性,这表明细菌具有一种新的防御机制.
相关概念视频
Single-Strand DNA Binding Proteins
14.1K
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...
14.1K
DNA Topoisomerases
31.3K
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. ...
Types and Mechanism of action
Topoisomerases are divided into two main types. ...
31.3K
Restriction Enzymes
30.7K
Restriction enzymes are bacterial enzymes used to cut DNA in a sequence-specific manner. To cleave DNA, they bind to specific palindromic sequences called restriction sites. Such palindromic DNA sequences or inverted repeats are commonly found in regions of functional significance, such as the origin of replication, gene operator sites, and regions containing transcription termination signals.
The host bacteria protect their own genomic DNA from these enzymes by methylating these sites. Some...
The host bacteria protect their own genomic DNA from these enzymes by methylating these sites. Some...
30.7K
Overview of DNA Repair
31.0K
In order to be passed through generations, genomic DNA must be undamaged and error-free. However, every day, DNA in a cell undergoes several thousand to a million damaging events by natural causes and external factors. Ionizing radiation such as UV rays, free radicals produced during cellular respiration, and hydrolytic damage from metabolic reactions can alter the structure of DNA. Damages caused include single-base alteration, base dimerization, chain breaks, and cross-linkage.
Chemically...
Chemically...
31.0K
Fixing Double-strand Breaks
12.6K
The double-stranded structure of DNA has two major advantages. First, it serves as a safe repository of genetic information where one strand serves as the back-up in case the other strand is damaged. Second, the double-helical structure can be wrapped around proteins called histones to form nucleosomes, which can then be tightly wound to form chromosomes. This way, DNA chains up to 2 inches long can be contained within microscopic structures in a cell. A double-stranded break not only damages...
12.6K
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


