Qin S, Nakajima B, Nomura M, Arfin S M
Department of Biological Chemistry, College of Medicine, University of California, Irvine 92717.
J Biol Chem. 1991 Aug 15;266(23):15549-54.
Ubiquitin-conjugating enzymes (E2s), which participate in the post-translational conjugation of ubiquitin to proteins, are encoded by a multigene family in the yeast Saccharomyces cerevisiae. E2s function in a variety of cellular activities including intracellular proteolysis, DNA repair, sporulation, and cell cycle traverse. Here, we report the cloning and characterization of a new member of the yeast UBC gene family, UBC8. UBC8 encodes a 206-amino acid protein containing a highly acidic carboxyl terminus. The primary structure of the protein is similar to that of all other known E2s, with the highest homology being to the E2 (23 kDa) of wheat germ. Haploid strains in which the UBC8 gene is disrupted are viable, and the disruption does not produce any obvious phenotype. The UBC8 protein, produced in Escherichia coli, forms thiol ester adducts with ubiquitin and, apparently, diubiquitin, but does not transfer ubiquitin to histones.
泛素缀合酶（E2s）参与泛素与蛋白质的翻译后缀合过程，由酿酒酵母中的一个多基因家族编码。E2s在多种细胞活动中发挥作用，包括细胞内蛋白质水解、DNA修复、孢子形成和细胞周期进程。在此，我们报告酵母UBC基因家族新成员UBC8的克隆及特性分析。UBC8编码一个含有高度酸性羧基末端的206个氨基酸的蛋白质。该蛋白质的一级结构与所有其他已知的E2s相似，与小麦胚芽的E2（23 kDa）同源性最高。UBC8基因被破坏的单倍体菌株是可存活的，且这种破坏不会产生任何明显的表型。在大肠杆菌中产生的UBC8蛋白与泛素以及显然还有双泛素形成硫酯加合物，但不会将泛素转移至组蛋白。
