Murai T, Kakizuka A, Takumi T, Ohkubo H, Nakanishi S
Institute for Immunology, Kyoto University, Faculty of Medicine, Japan.
Biochem Biophys Res Commun. 1989 May 30;161(1):176-81. doi: 10.1016/0006-291x(89)91577-5.
The amino acid sequence for a novel human membrane protein that induces selective potassium permeation by membrane depolarization was deduced by molecular cloning and sequence analysis of its genomic DNA. This protein consists of 129 amino acid residues and shares several structural characteristics with the rat counterpart. These include a single putative transmembrane domain surrounded by many charged amino acid residues, two potential N-glycosylation sites at the amino-terminal portion and a single cysteine residue at the carboxyl-terminal portion. The transmembrane domain and its flanking carboxyl-terminal sequence are highly conserved between the human and rat sequences. Because the slowly activating potassium current elicited by the human protein on its expression in Xenopus oocytes is indistinguishable from that induced by the rat protein, the sequence conserved at the transmembrane domain and its following sequence should play an essential role in the induction of selective K+ permeation.
通过对其基因组DNA进行分子克隆和序列分析，推导了一种新型人类膜蛋白的氨基酸序列，该蛋白通过膜去极化诱导选择性钾通透。这种蛋白质由129个氨基酸残基组成，与大鼠对应物具有几个结构特征。这些特征包括一个被许多带电荷氨基酸残基包围的单一推定跨膜结构域、氨基末端部分的两个潜在N-糖基化位点以及羧基末端部分的一个半胱氨酸残基。人类和大鼠序列之间的跨膜结构域及其侧翼羧基末端序列高度保守。由于人类蛋白在非洲爪蟾卵母细胞中表达时引发的缓慢激活钾电流与大鼠蛋白诱导的电流无法区分，因此跨膜结构域及其后续序列中保守的序列在诱导选择性K+通透中应起重要作用。
