The human 26 S and 20 S proteasomes generate overlapping but different sets of peptide fragments from a model protein substrate
The human 26 S and 20 S proteasomes generate overlapping but different sets of peptide fragments from a model protein substrate
复制标题
DOI：
10.1074/jbc.m000740200
复制
发表时间：
2000-07-14
影响因子：
4.8
通讯作者：
Schild, H
中科院分区：
文献类型：
--
作者：
Emmerich, NPN;Nussbaum, AK;Schild, H
细胞内蛋白质降解是短抗原肽的主要来源，在主要的组织兼容性I类分子的背景下，可以在细胞表面呈现，以通过细胞毒性T淋巴细胞识别。已彻底研究了最重要的胞质蛋白酶20 s蛋白酶体的能力，即产生平均长度为7-8氨基酸残基的肽片段。已经表明，切割产物不是随机生成的，而是源自催化活性亚基对原代氨基酸序列中复杂识别基序的承诺。但是，更大的26 s蛋白酶体的作用较不明显。已经证明，26 S蛋白酶体可以在体内和体外结合和降解泛素标记的蛋白和微基翻译产物，但是降解产物的性质仍然难以捉摸。在这项研究中，我们介绍了对未修饰的模型底物β-蛋白的体外消化的裂解产物的首次分析，并具有26 s和20 s蛋白酶体。我们获得的数据表明，26 s和20 s的蛋白酶组会产生重叠，但同时通过遵循非常相似的说明，基本不同的片段集。
Intracellular protein degradation is a major source of short antigenic peptides that can be presented on the cell surface in the context of major histocompatibility class I molecules for recognition by cytotoxic T lymphocytes. The capacity of the most important cytosolic protease, the 20 S proteasome, to generate peptide fragments with an average length of 7-8 amino acid residues has been thoroughly investigated. It has been shown that the cleavage products are not randomly generated, but originate from the commitment of the catalytically active subunits to complex recognition motifs in the primary amino acid sequence. The role of the even larger 26 S proteasome is less well defined, however. It has been demonstrated that the 26 S proteasome can bind and degrade ubiquitin-tagged proteins and minigene translation products in vivo and in vitro, but the nature of the degradation products remains elusive. In this study, we present the first analysis of cleavage products from in vitro digestion of the unmodified model substrate beta-casein with both the 26 S and 20 S proteasome. The data we obtained show that 26 S and 20 S proteasomes generate overlapping, but at the same time substantially different, sets of fragments by following very similar instructions.