IDENTIFICATION OF THE MEMBRANE ATTACHMENT SITES FOR PROTEIN-4.1 IN THE HUMAN ERYTHROCYTE
IDENTIFICATION OF THE MEMBRANE ATTACHMENT SITES FOR PROTEIN-4.1 IN THE HUMAN ERYTHROCYTE
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DOI：
10.1074/jbc.270.10.5360
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发表时间：
1995-03-10
影响因子：
4.8
通讯作者：
MOHANDAS, N
中科院分区：
文献类型：
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作者：
HEMMING, NJ;ANSTEE, DJ;MOHANDAS, N
人红细胞膜蛋白4.1的膜结合位点(S)的性质尚未完全阐明。在本文中，我们证明了糖蛋白(GP)C/D是主要的结合位点，纯化的蛋白4.1可以结合到血糖蛋白C/D上的两个不同的位点，其中一个是直接相互作用，涉及血糖蛋白C上的82-98个残基(血糖蛋白D上的61-77个残基)，而另一个相互作用是由P55介导的。我们已将血糖蛋白C上P55的结合部位定位为112-128位(血糖素D91-107)。我们还提供了条带3是额外的、次要的蛋白质4.1结合位点的证据。带3、血糖蛋白C/D和P55的结合部位都位于蛋白质4.1的30 kDa区域内。我们估计，在正常膜上，这三个位点的相对利用率分别为40%到P55，40%到GPC/D，20%到带3。蛋白4.1的同一区域结合GPC/D和带3，而P55结合位置是不同的。蛋白质4.1与P55和P55与GPC/D具有高亲和力，而与GPC/D和带3的相互作用则低100倍(MuM)。这些结果表明，蛋白质4.1与膜之间最显著的相互作用是涉及P55的相互作用。
The nature of the membrane attachment site(s) for protein 4.1 in the human erythrocyte membrane has yet to be fully elucidated. In this paper we show that the major attachment site is glycophorin (GP) C/D, and that purified protein 4.1 can bind to two distinct sites on glycophorin C/D. One of these interactions is direct, involving residues 82-98 on glycophorin C (61-77 on glycophorin D), while the other interaction is mediated by p55. We have localized the binding site for p55 on glycophorin C to residues 112-128 (glycophorin D 91-107). We also provide evidence that band 3 is an additional, minor, protein 4.1 binding site. The binding sites for band 3, glycophorin C/D, and p55 are all located within the 30-kDa domain of protein 4.1. We estimate that the relative utilization of the three sites in normal membranes comprises 40% to p55, 40% to GPC/D, and 20% to band 3. The same region of protein 4.1 binds GPC/D and band 3, while the p55 binding site is distinct. The interactions involving protein 4.1 with p55 and p55 with GPC/D are of high affinity (nM), while those involving GPC/D and band 3 are 100 fold lower (mu M). These results suggest that the most significant interactions between protein 4.1 and the membrane are those involving p55.