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一种与染色质结合的蛋白质分解活性,具有独特的特异性,用于 histone H2A
Cell
|December 1, 1976
概括
一个核蛋白酶在其碳氧终端端切割了基因组H2A,创建了一个新的片段. 这种特定的裂变需要高的离子强度,这表明依赖于形状的反应.
科学领域:
- 生物化学 生物化学
- 分子生物学分子生物学
- 染色体生物学 染色体生物学
背景情况:
- 基因组蛋白对于染色质中的DNA包装至关重要.
- 基因组的蛋白质分解性修饰可以改变色素的结构和功能.
- 参与基因素修饰的特定蛋白酶尚未完全表征.
研究的目的:
- 为了识别和描述与小牛胸腺染色素相关的蛋白酶.
- 为了确定已识别的蛋白酶的基质特异性和裂变部位.
- 为了研究影响蛋白质分解活性的条件.
主要方法:
- 纯化小牛胸腺染色质的纯化.
- 基因素H2A与相关的蛋白酶的酶性消化.
- 使用烯胺凝电泳分析分析得到的碎片 (cH2A).
- 氨基酸分析和cH2A的部分测序.
- 在不同的离子强度条件下对蛋白酶活性的研究.
主要成果:
- 鉴定出了一种蛋白酶,该蛋白酶能够分离 histone H2A,产生一个碎片 (cH2A).
- cH2A是从H2A的C末端去除15个氨基酸的结果,瓦林114作为新的C末端残留物.
- 蛋白质分解活性取决于高离子强度,这表明特定于形状的裂变.
- 蛋白酶是核起源的,与染色质密切相关,需要1.2M NaCl进行解离.
结论:
- 已经确定了一种与染色质相关的新型H2A特异性核蛋白酶.
- 蛋白酶表现出依赖于形状的裂变特异性,受离子强度的影响.
- 这种酶在细胞核内的基因子修饰中起作用.
相关概念视频
The Nucleosome Core Particle
Nucleosomes are the DNA-histone complex, where the DNA strand is wound around the histone core. The histone core is an octamer containing two copies of H2A, H2B, H3, and H4 histone proteins.
The paradox
Nucleosomes, paradoxically, perform two opposite functions simultaneously. On the one hand, their main responsibility is to protect the delicate DNA strands from physical damage and help achieve a higher compaction ratio. While on the other hand, they must allow polymerase enzymes to access DNA...
The paradox
Nucleosomes, paradoxically, perform two opposite functions simultaneously. On the one hand, their main responsibility is to protect the delicate DNA strands from physical damage and help achieve a higher compaction ratio. While on the other hand, they must allow polymerase enzymes to access DNA...
Histone Modification
The histone proteins have a flexible N-terminal tail extending out from the nucleosome. These histone tails are often subjected to post-translational modifications such as acetylation, methylation, phosphorylation, and ubiquitination. Particular combinations of these modifications form “histone codes” that influence the chromatin folding and tissue-specific gene expression.
Acetylation
The enzyme histone acetyltransferase adds acetyl group to the histones. Another enzyme, histone deacetylase,...
Acetylation
The enzyme histone acetyltransferase adds acetyl group to the histones. Another enzyme, histone deacetylase,...
Spreading of Chromatin Modifications
The histone proteins in the nucleosomes are post-translationally modified (PTM) to increase or decrease access to DNA. The commonly observed PTMs are methylation, acetylation, phosphorylation, and ubiquitination of lysine amino acids in the histone H3 tail region. These histone modifications have specific meaning for the cell. Hence, they are called "histone code". The protein complex involved in histone modification is termed as "reader-writer" complex.
Writers
The writer is an enzyme that can...
Writers
The writer is an enzyme that can...
Euchromatin
The extent of chromatin compaction can be studied by staining chromatin using specific DNA binding dyes. Under the microscope, the dense-compacted regions take up more dye, appearing darker, while the less-compact areas take up less dye and appear lighter. Based on the compaction level, chromatins are classified into two primary forms – euchromatin and heterochromatin.
Euchromatin is the less dense region of the chromatin and stains lighter. Euchromatin contains histone H3 extensively...
Euchromatin is the less dense region of the chromatin and stains lighter. Euchromatin contains histone H3 extensively...
Heterochromatin
The extent of chromatin compaction can be studied by staining chromatin using specific DNA binding dyes. Under the microscope, the dense-compacted regions that take up more dye are called heterochromatin. Heterochromatin is further classified into two forms – constitutive heterochromatin and facultative heterochromatin.
Constitutive heterochromatin: It is a highly compact region of chromatin that is mostly concentrated in the centromere and telomere. Unlike euchromatin, the amino acid at 9th...
Constitutive heterochromatin: It is a highly compact region of chromatin that is mostly concentrated in the centromere and telomere. Unlike euchromatin, the amino acid at 9th...
The Nucleosome Core Particle
Nucleosomes are the DNA-histone complex, where the DNA strand is wound around the histone core. The histone core is an octamer containing two copies of H2A, H2B, H3, and H4 histone proteins.
Nucleosomes, paradoxically, perform two opposite functions simultaneously. On the one hand, their primary aim is to protect the delicate DNA strands from physical damage and help achieve a higher compaction ratio. On the other hand, they must allow polymerase enzymes to access histone-bound DNA during...
Nucleosomes, paradoxically, perform two opposite functions simultaneously. On the one hand, their primary aim is to protect the delicate DNA strands from physical damage and help achieve a higher compaction ratio. On the other hand, they must allow polymerase enzymes to access histone-bound DNA during...

