Discrete cross-linking products identified during membrane protein biosynthesis
Discrete cross-linking products identified during membrane protein biosynthesis
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DOI：
10.1074/jbc.272.3.1983
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发表时间：
1997-01-17
影响因子：
4.8
通讯作者：
High, S
中科院分区：
文献类型：
--
作者：
Laird, V;High, S
我们研究了多跨膜蛋白视蛋白的膜插入的分子细节。利用异双功能交联试剂测定了内质网（ER）蛋白与一系列确定的易位中间体相邻。一旦新生的视蛋白链达到临界最小长度，Sec61 α就成为与多肽相邻的主要内质网成分。利用同型双功能试剂，分析了新生链中单个半胱氨酸残基的交联伙伴。该方法鉴定了新生视蛋白与21 kda核糖体蛋白之间的链长依赖交联产物，其次是Sec61 β，最后是Sec61 α。我们的数据支持一个模型，其中多跨膜蛋白的顺序跨膜结构域整合在内质网插入位点，类似于介导单跨膜蛋白插入的结构域。
We have investigated the molecular details of the membrane insertion of the multiple-spanning membrane protein opsin. Using heterobifunctional cross linking reagents the endoplasmic reticulum (ER) proteins adjacent to a series of defined translocation intermediates were determined. Once the nascent opsin chain reaches a critical minimum length Sec61 alpha is the major ER component adjacent to the polypeptide. Using a homobifunctional reagent, the cross-linking partners from a single cysteine residue in the nascent chain were analyzed. This approach identified chain length-dependent cross-linking products between nascent opsin and a 21-kDa ribosomal protein, followed by Sec61 beta and finally with Sec61 alpha. Our data support a model where the sequential transmembrane domains of a multiple-spanning membrane protein are integrated at an ER insertion site similar to that mediating the insertion of single-spanning membrane proteins.