Johnson E S, Gonda D K, Varshavsky A
Department of Biology, Massachusetts Institute of Technology, Cambridge 02139.
Nature. 1990 Jul 19;346(6281):287-91. doi: 10.1038/346287a0.
The N-end rule, a code that relates the metabolic stability of a protein to the identity of its amino-terminal residue, is universal in that different versions of the N-end rule operate in mammals, yeast and bacteria (unpublished data). The N-end rule-based degradation signal comprises a destabilizing amino-terminal residue and a specific internal lysine residue. We now show that, in a multisubunit protein, these two determinants can be located on different subunits and still target the protein for destruction. Moreover, in this case (trans recognition) only the subunit that bears the lysine determinant is actually degraded. Thus an oligomeric protein can contain both short-lived and long-lived subunits. These insights have functional and practical implications.
N端规则是一种将蛋白质的代谢稳定性与其氨基末端残基的特性相关联的编码，它具有普遍性，因为不同版本的N端规则在哺乳动物、酵母和细菌中都起作用（未发表的数据）。基于N端规则的降解信号包括一个不稳定的氨基末端残基和一个特定的内部赖氨酸残基。我们现在表明，在一个多亚基蛋白质中，这两个决定因素可以位于不同的亚基上，并且仍然能将该蛋白质靶向降解。此外，在这种情况下（反式识别），实际上只有带有赖氨酸决定因素的亚基会被降解。因此，一个寡聚蛋白可以同时包含短命和长寿的亚基。这些见解具有功能和实际意义。
