A MULTIUBIQUITIN CHAIN IS CONFINED TO SPECIFIC LYSINE IN A TARGETED SHORT-LIVED PROTEIN
A MULTIUBIQUITIN CHAIN IS CONFINED TO SPECIFIC LYSINE IN A TARGETED SHORT-LIVED PROTEIN
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DOI：
10.1126/science.2538923
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发表时间：
1989-03-24
期刊：
影响因子：
56.9
通讯作者：
VARSHAVSKY, A
中科院分区：
文献类型：
--
作者：
CHAU, V;TOBIAS, JW;VARSHAVSKY, A
测试蛋白β的泛素依赖性降解半乳糖苷酶（beta.gal）之前是β gal的泛素化。许多（从1个到20个以上）泛素部分连接到分子上beta.gal作为分支泛素-泛素缀合物的有序链出现，其中一个泛素的羧基末端Gly 76连接到相邻泛素的内部Lys 48。该多遍在蛋白链与β gal中的两个特异性Lys残基之一连接。这些相同的Lys残基已通过分子遗传分析鉴定为β gal中氨基末端降解信号的组分。泛素在其Lys 48残基处突变的实验表明，靶蛋白中的多泛素链对于蛋白质的降解是必需的。
The ubiquitin-dependent degradation of a test protein .beta.-galactosidase (.beta.gal) is preceded by ubiquitination of .beta.gal. The many (from 1 to more than 20) ubiquitin moieties attached to a molecule of .beta.gal occur as an ordered chain of branched ubiquitin-ubiquitin conjugates in which the carboxyl-terminal Gly76 of one ubiquitin is joined to the internal Lys48 of an adjacent ubiquitin. This multiubiquitin chain is linked to one of two specific Lys residues in .beta.gal. These same Lys residues have been identified by molecular genetic analysis as components of the amino-terminal degradation signal in .beta.gal. The experiments with ubiquitin mutated at its Lys48 residue indicate that the muliubiquitin chain in a targeted protein is essential for the degradation of the protein.