Unique topology of the internal repeats in the cardiac Na+/Ca2+ exchanger
Unique topology of the internal repeats in the cardiac Na+/Ca2+ exchanger
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DOI：
10.1016/s0014-5793(99)00218-5
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发表时间：
1999-03-12
期刊：
影响因子：
3.5
通讯作者：
Shigekawa, M
中科院分区：
文献类型：
--
作者：
Iwamoto, T;Nakamura, TY;Shigekawa, M
水病分析预测心脏Na+/Ca~(2+)交换器中有11个跨膜螺旋。利用半胱氨酸敏感性分析和表位标记，我们研究了交换器的膜拓扑结构，特别是高度保守的内部α-1和α-2重复序列。出人意料的是，Ne发现α-1重复序列中的连接环形成了一个可重入的膜环，两端面向细胞外一侧，一个残基(ASN-125)可以从内部进入，而包含α-2重复序列的区域大多可以从细胞质进入。结合其他数据，我们推测该交换器可能由9个跨膜螺旋组成。(C)1999年欧洲生化学会联合会。
Hydropathy analysis predicts 11 transmembrane helices in the cardiac Na+/Ca2+ exchanger. Using cysteine susceptibility analysis and epitope tagging, we here studied the membrane topology of the exchanger, in particular of the highly conserved internal alpha-1 and alpha-2 repeats. Unexpectedly, ne found that the connecting loop in the alpha-1 repeat forms a re-entrant membrane loop with both ends facing the extracellular side and one residue (Asn-125) being accessible from the inside and that the region containing the alpha-2 repeat is mostly accessible from the cytoplasm. Together with other data, we propose that the exchanger may consist of nine transmembrane helices. (C) 1999 Federation of European Biochemical Societies.