Structure and assembly of the 20S proteasome
Structure and assembly of the 20S proteasome
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DOI：
10.1007/s000180050147
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发表时间：
1998-03
期刊：
影响因子：
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通讯作者：
W. Gerards;W. D. Jong;W. Boelens;Hans Bloemendal
中科院分区：
文献类型：
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作者：
W. Gerards;W. D. Jong;W. Boelens;Hans Bloemendal
桶形的20 S蛋白酶体是一个更大的26 S颗粒，多催化2000-kDa蛋白酶复合物的两个组成部分之一。蛋白水解位点位于20 S颗粒的内室中，只能通过狭窄的入口进入。本文综述了目前有关蛋白酶体的形成，蛋白水解活性，结构方面和组装的知识。真核蛋白酶体由四个环组成，每个环包含七个不同的亚基，位于固定位置。而外环包含α-型亚基，内环包含β-型亚基。目前的真核20 S蛋白酶体组装模型是基于13 S和16 S中间体的检测，除了以前的研究结果与古细菌和真细菌蛋白酶体组装。现有的数据表明，α-型和β-型亚基协同组装成半蛋白酶体样复合物，然后二聚成蛋白酶体。在半蛋白酶体二聚化期间或之后，β-型亚基被加工。β-型亚基的前序列对于装配过程是必需的，并且防止未成熟蛋白酶体的蛋白酶活性。
The barrel-shaped 20S proteasome is one of the two components of a larger 26S particle, the multicatalytic 2000-kDa protease complex. The proteolytic sites are located in the inner chamber of the 20S particle and are only accessible via narrow entrances. This paper reviews the current knowledge concerning proteasome formation, proteolytic activities, structural aspects and assembly. Eukaryotic proteasomes are made up by four rings each of which contains seven different subunits occurring at fixed positions. While the outer rings containα-type subunits, the inner ones compriseβ-type subunits. The current assembly model for eukaryotic 20S proteasomes is based upon the detection of 13S and 16S intermediates, respectively, in addition to previous findings with archaebacterial and eubacterial proteasome assembly. The available data suggest a cooperative assembly of theα-type andβ-type subunits into half proteasome-like complexes followed by dimerization into proteasomes. During or after dimerization of half proteasomes, theβ-type subunits are processed. The prosequence of theβ-type subunits is essential for the assembly process and prevents protease activity of immature proteasomes.