Biosynthesis of electroplax sodium channels in Electrophorus electrocytes and Xenopus oocytes.
Biosynthesis of electroplax sodium channels in Electrophorus electrocytes and Xenopus oocytes.
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Electrophorus 电细胞和非洲爪蟾卵母细胞中 electroplax 钠通道的生物合成。
DOI：
10.1021/bi00388a029
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发表时间：
1987
期刊：
影响因子：
2.9
通讯作者：
Levinson,SR
中科院分区：
文献类型：
--
作者：
Thornhill,WB;Levinson,SR
生理学系，医学院，科罗拉多大学健康科学中心，丹佛，科罗拉多80262接收日期：1986年12月9日;修订后的手册接收日期：1987年3月16日摘要：我们已经在无细胞和青蛙卵母细胞系统中合成了鳗鱼电泳钠通道核心多肽，并报道它不具有成熟的不寻常的电泳特性，从electroplax膜分离的天然钠通道多肽。在十二烷基硫酸钠-聚丙烯酰胺凝胶电泳上，成熟通道多肽表现出弥散带型（微异质性）和极高的电泳自由迁移率。与此相反，在体外或体内合成的核心多肽迁移作为一个尖锐的带与近正常的电泳自由迁移率（先生230000）。成熟肽的微观异质性被推断是由通道多肽不同程度的糖基化引起的[米勒，J.A.，Agnew，W.美国，& Levinson，S. R.（1983）Biochemistry 22，462-470]，我们在此提供的证据表明，异常高的电泳自由迁移率是由于大量十二烷基硫酸钠与蛋白质上的后修饰结构域的结合。此外，我们还跟踪了鳗鱼钠通道在鳗鱼电细胞和青蛙卵母细胞中的翻译后加工。使用凝集素结合和弗格森分析，我们发现，该通道被处理相对较快的中间形式，显然含有较少的碳水化合物和疏水结构域比成熟的通道中的高尔基体。进一步添加碳水化合物和疏水结构域，这是需要之前的通道获得其特有的物理化学性质，进行相对缓慢的electrocyte和出现没有发生大多数的中间处理channels in的青蛙卵母细胞。
Department of Physiology, School of Medicine, University of Colorado Health Sciences Center, Denver, Colorado 80262 Received December 9, 1986; Revised Manuscript Received March 16, 1987 abstract: We have synthesized the eel electroplax sodium channel core polypeptide in both a cell-free and a frog oocyte system and report it does not possess the unusual electrophoretic properties of the mature, native sodium channel polypeptide isolated from electroplax membranes. On sodium dodecyl sulfate-polyacrylamide gel electrophoresis, the mature channel polypeptideexhibits both a diffuse banding pattern (microheterogeneity) and an extremely high electrophoretic free mobility. In contrast, the core polypeptide synthesized in vitro or in vivo migrates as a sharp band with a near-normal electrophoretic free mobility (Mr 230000). The microheterogeneity of the mature peptide has been inferred to result from varying degrees of glycosylation of the channel polypeptide [Miller, J. A., Agnew, W. S., & Levinson, S. R.(1983) Biochemistry 22, 462-470], Wepresent evidence here that the anomalously high electrophoretic free mobility is due tothe binding of large amounts of sodium dodecyl sulfate to posttranslationally modified domains on the protein. In addition, we have followed the posttranslational processing of eel sodium channels in both the eel electrocyte and the frog oocyte. Using lectin binding and Ferguson analysis, we found that the channel was processed relatively rapidly to an intermediate form in the Golgi apparatus that apparently contained fewer carbohydrate and hydrophobic domains than the mature channel. The further addition of carbohydrate and hydrophobic domains, which are required before the channel acquires its characteristic physicochemical properties, proceeded relatively slowly in the electrocyte and appeared not to have occurred to the majority of intermediately processed channelsin the frog oocyte.