类型: 类型: 类型: 类型: 类型: 类型: 类型: 类型: 类型: 类型: 类型: 类型: 类型:
Kabira Sabnam1, Swagata Dasgupta1
1Department of Chemistry, Indian Institute of Technology Kharagpur, Kharagpur, India.
Proteins
|April 4, 2025
概括
类型:类型: 类型: 类型: 类型: 类型: 类型: 类型: 类型: 类型: 类型: 类型: 类型: 类型: 类型: 类型: 类型: 类型: 类型: 类型: 类型: 类型: 类型: 类型: 类型: 类型: 类型: 类型: 类型: 这项研究揭示了修饰RNase A的结构变化和功能障碍,为疾病机制提供了洞察力.
科学领域:
- 生物化学 生物化学
- 分子生物学分子生物学
- 蛋白质组学是指蛋白质组学.
背景情况:
- 高水平的homocysteine thiolactone与各种人类疾病有关.
- N-homocysteinylation 修改了蛋白质中的 lysine 残留物,可能导致二聚化和寡聚化.
- 了解蛋白质修饰对于破译疾病病理学至关重要.
研究的目的:
- 研究N-homocysteinylation对Ribonuclease A (RNase A) 的结构和功能影响.
- 阐明 homocysteine thiolactone 修饰如何影响 RNase A 的活性和完整性.
- 为了解与高homocysteinemia相关的病理学作出贡献.
主要方法:
- 二甲基硫酸盐-聚烯胺凝电泳 (SDS-PAGE) 和矩阵辅助激光缩/电离-飞行时间 (MALDI-ToF) 质谱测量以确认蛋白质寡合化.
- 阿加罗斯凝测试以评估核核分解活性.
- 光光谱检测氨酸微环境中的变化.
- 循环二元化 (CD) 融研究,以分析二次结构变化.
- 异热定位热量计 (ITC) 和紫外线可见动力学以量化酶活性.
主要成果:
- 对RNase A的N-homocysteinylation导致二元体和更高阶寡聚体的形成.
- 修改后的RNase A表现出减少的核核分裂活性.
- 谱学和CD分析表明局部结构变化,包括二次结构含量改变 (增强β-sheet,减少α-helix),但整体结构完整性保持.
- ITC和动力学研究证实,在同型化时酶活性显著下降.
结论:
- N-homocysteinylation诱导RNase A的显著结构和功能变化.
- 观察到的RNase A的变化为了解超同菌素血症对蛋白质功能的影响提供了分子基础.
- 这项研究增强了我们对homocysteine thiolactone如何对疾病发病的贡献的理解.
相关概念视频
Phase II Reactions: Glutathione Conjugation and Mercapturic Acid Formation
111
Glutathione, a tripeptide made up of glutamate, cysteine, and glycine, is a critical player in the detoxification of drugs and xenobiotics via a process known as glutathione conjugation or mercapturic acid formation. This phase II biotransformation reaction involves the covalent binding of glutathione to a drug or its metabolite, enhancing the compound's water solubility and enabling its excretion.
Several distinctive characteristics distinguish glutathione conjugation from other phase II...
Several distinctive characteristics distinguish glutathione conjugation from other phase II...
111
Transfer RNA Synthesis
11.8K
One of the unique features of tRNA is the presence of modified bases. In some tRNAs, modified bases account for nearly 20% of the total bases in the molecule. Altogether, these unusual bases protect the tRNA from enzymatic degradation by RNases.
Each of these chemical modifications is carried by a specific enzyme, post-transcription. All of these enzymes have unique base and site-specificity. Methylation, the most common chemical modification, is carried by at least nine different enzymes, with...
Each of these chemical modifications is carried by a specific enzyme, post-transcription. All of these enzymes have unique base and site-specificity. Methylation, the most common chemical modification, is carried by at least nine different enzymes, with...
11.8K
Ribozymes
11.0K
The term ribozyme is used for RNA that can act as an enzyme. Ribozymes are mainly found in selected viruses, bacteria, plant organelles, and lower eukaryotes. Ribozymes were first discovered in 1982 when Tom Cech’s laboratory observed Group I introns acting as enzymes. This was shortly followed by the discovery of another ribozyme, Ribonulcease P, by Sid Altman’s laboratory. Both Cech and Altman received the Nobel Prize in chemistry in 1989 for their work on ribozymes.
Ribozymes can...
Ribozymes can...
11.0K
Introduction to Mechanisms of Enzyme Catalysis
7.8K
For many years, scientists thought that enzyme-substrate binding took place in a simple "lock-and-key" fashion. This model stated that the enzyme and substrate fit together perfectly in one instantaneous step. However, current research supports a more refined view scientists call induced fit. The induced-fit model expands upon the lock-and-key model by describing a more dynamic interaction between enzyme and substrate. As the enzyme and substrate come together, their interaction causes...
7.8K
Regioselective Formation of Enolates
2.5K
As depicted in the figure below, the unsymmetrical ketones can form two possible enolates: less substituted or more substituted enolates. Usually, the thermodynamic enolates are formed from the more substituted α-carbon atom, while the kinetic enolates are formed faster by deprotonation from the less substituted position. The thermodynamic enolates have lower energy, so they are more stable. But the energy required to form kinetic enolates is less.
2.5K
RNA Stability
33.1K
Intact DNA strands can be found in fossils, while scientists sometimes struggle to keep RNA intact under laboratory conditions. The structural variations between RNA and DNA underlie the differences in their stability and longevity. Because DNA is double-stranded, it is inherently more stable. The single-stranded structure of RNA is less stable but also more flexible and can form weak internal bonds. Additionally, most RNAs in the cell are relatively short, while DNA can be up to 250 million...
33.1K


