Erythrocyte Mr 28,000 transmembrane protein exists as a multisubunit oligomer similar to channel proteins.
Erythrocyte Mr 28,000 transmembrane protein exists as a multisubunit oligomer similar to channel proteins.
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DOI：
10.1016/s0021-9258(18)38133-x
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发表时间：
1991-04
期刊：
影响因子：
--
通讯作者：
Barbara L. Smith;P. Agre
中科院分区：
文献类型：
--
作者：
Barbara L. Smith;P. Agre
最近纯化了一种新的Mr 28，000红细胞跨膜蛋白，并发现其以两种形式存在，“28 kDa”和“gly 28 kDa”，后者含有N-连接的碳水化合物（Denker，B. M.，史密斯，B。L.，Kuhajda，F. P.的人，和Agre，P.（1988）J.Biol.Chem.263，15634-15642）。虽然28 kDa蛋白质类似的Rh多肽生物化学，结构同源性没有确定免疫印迹或二维碘肽图。纯化的28 kDa蛋白质的前35个残基的NH 2-末端氨基酸序列与透镜的26-kDa主要内在蛋白质具有37%的同一性（Gorin，M. B.，Yancey，S. B.，克莱恩，J。，Revel，J.- P.，和Horwitz，J. Cell 39，49-59）。抗血清的合成肽对应的NH 2-末端的28 kDa蛋白给出了一个单一的反应，分子量28 kDa的红细胞膜上的免疫印迹。选择性digestion完整的红细胞和内面外膜囊泡与羧肽酶Y表明存在一个5 kDa的COOH-末端胞质结构域。多项研究表明，28 kDa和gly 28 kDa蛋白作为多亚基寡聚体一起存在：1）在Triton X-100中的相似部分溶解; 2）在离子交换和凝集素亲和层析期间的共纯化; 3）在低浓度戊二醛中交联;和4）在1%（v/v）TritonX中纯化的蛋白质和溶解的膜的物理分析。100表明，28 kDa和gly 28 kDa蛋白表现为一个大的单一单位，Stokes半径为61 A，沉降系数为5.7 S。这些研究表明，28 kDa和gly 28 kDa蛋白质是不同的Rh多肽和存在的多亚基寡聚体。该28 kDa蛋白质具有NH 2-末端氨基酸序列同源性和膜组织类似于主要内在蛋白和新认识的跨膜通道蛋白家族的其他成员。
A novel Mr 28,000 erythrocyte transmembrane protein was recently purified and found to exist in two forms, “28kDa” and “gly28kDa,” the latter containing N-linked carbohydrate (Denker, B. M., Smith, B. L., Kuhajda, F. P., and Agre, P. (1988) J. Biol. Chem. 263, 15634-15642). Although 28kDa protein resembles the Rh polypeptides biochemically, structural homologies were not identified by immunoblot or two-dimensional iodopeptide maps. The NH2-terminal amino acid sequence for the first 35 residues of purified 28kDa protein is 37% identical to the 26-kDa major intrinsic protein of lens (Gorin, M. B., Yancey, S. B., Cline, J., Revel, J.-P., and Horwitz, J. Cell 39, 49-59). Antisera to a synthetic peptide corresponding to the NH2-terminus of 28kDa protein gave a single reaction of molecular mass 28kDa on immunoblots of erythrocyte membranes. Selective digestions of intact erythrocytes and inside-out membrane vesicles with carboxypeptidase Y indicated the existence of a 5-kDa COOH-terminal cytoplasmic domain. Multiple studies indicated that 28kDa and gly28kDa proteins exist together as a multisubunit oligomer: 1) similar partial solubilizations in Triton X-100; 2) co-purification during ion exchange and lectin affinity chromatography; 3) cross-linking in low concentrations of glutaraldehyde; and 4) physical analyses of purified proteins and solubilized membranes in 1% (v/v) Triton X-100 showed 28kDa and gly28kDa proteins behave as a large single unit with Stokes radius of 61 A and sedimentation coefficient of 5.7 S. These studies indicate that the 28kDa and gly28kDa proteins are distinct from the Rh polypeptides and exist as a multisubunit oligomer. The 28kDa protein has NH2-terminal amino acid sequence homology and membrane organization similar to major intrinsic protein and other members of a newly recognized family of transmembrane channel proteins.