THE PROTEIN-CONDUCTING CHANNEL

蛋白质传导通道

• 批准号: 7723601
• 负责人: JAMES C GUMBART
• 金额: $ 4.74万
• 依托单位: UNIVERSITY OF ILLINOIS AT URBANA-CHAMPAIGN
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-08-01 至 2009-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7723601
• 关键词: Archaea; Back; Bacteria; Be++ element; Behavior; Beryllium; Cell membrane; Cells; Complex; Computer Retrieval of Information on Scientific Projects Database; Endoplasmic Reticulum; Eukaryota; Eukaryotic Cell; Feeds; Funding; Grant; Institution; Insulin; Left; Life; Membrane; Membrane Proteins; Methanococcus; Prions; Proteins; Research; Research Personnel; Resolution; Resources; Ribosomes; Role; Source; Structure; United States National Institutes of Health; base; dimer; in vivo; monomer; polypeptide

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The protein-conducting channel, more specifically known as the translocon (http://www.ks.uiuc.edu/Research/translocon/) or Sec complex, is an evolutionarily ancient protein complex that helps proteins cross or integrate into membranes (depending on whether they are soluble or membrane proteins). Present in all branches of life, the Sec complex is found in the cytoplasmic membrane in bacteria and archaea and in the membrane of the endoplasmic reticulum in eukaryotes. A passive channel, the Sec complex partners with other proteins that drive translocation of an unfolded polypeptide through the channel. In co-translational translocation, a common mode of translocation, this partner is the ribosome which feeds the nascent protein through the channel as it is synthesized. As a key step in protein targeting, translocation can be a deciding factor in the fate of proteins and even the cell as a whole. For example, poor recognition of the prion protein (PrP) leads to its abnormal aggregation and ultimately to lethal levels in the cell [1]. However, being able to enhance recognition and passage across the membrane could increase yields for artificially created proteins such as insulin [2]. In 2004, the Resource's collaborator, Tom Rapoport, released the first high resolution structure of the translocon. Obtained from Methanococcus jannaschii, this heterotrimeric membrane protein complex was resolved to 3.5 Angstroms. Based on this structure, specific details of translocation began to emerge. Observed structural elements were proposed to have specific functions, such as a constrictive pore ring and a plug blocking the exit of the channel. It was also proposed that a singular monomer within a dimeric or tetrameric complex serves as the active channel, leaving the role of oligomerization in question. Two dimeric forms of the channel with different functional behavior have been proposed (a 'back-to-back' and a 'front-to-front' dimer) although which is the in vivo state is unknown.

该副本是利用众多研究子项目之一 由NIH/NCRR资助的中心赠款提供的资源。子弹和 调查员（PI）可能已经从其他NIH来源获得了主要资金， 因此可以在其他清晰的条目中代表。列出的机构是 对于中心，这不一定是调查员的机构。 蛋白质传导通道，更特别地称为易位（http://www.ks.uiuc.edu/research/research/translocon/）或SEC复合物，是一种进化上古老的蛋白质复合物，可帮助蛋白质交叉或整合到膜中（取决于它们是溶解或膜蛋白）。 SEC复合物存在于生命的所有分支中，在细菌和古细菌的细胞质膜中以及真核生物中内质网的膜中发现。 SEC复合物与其他蛋白质合作的被动通道，这些蛋白质可以通过通道驱动展开的多肽易位。在共同翻译（一种常见的易位方式）中，该伴侣是核糖体，该核糖体在合成的过程中通过通道喂养新生蛋白。作为蛋白质靶向的关键步骤，易位可能是蛋白质命运甚至整个细胞的决定因素。例如，对prion蛋白（PRP）的识别不良导致其异常聚集，最终导致细胞中的致命水平[1]。 但是，能够增强识别和通过整个膜的识别可能会增加人为产生的蛋白质（例如胰岛素）的产量[2]。 2004年，资源的合作者汤姆·拉波波特（Tom Rapoport）发布了Cranslocon的第一个高分辨率结构。从Jannaschii获得的，将这种异三聚体膜蛋白复合物分辨到3.5埃埃斯特罗姆。基于这种结构，易位的具体细节开始出现。提出观察到的结构元素具有特定的功能，例如收缩的孔环和插头阻塞通道的出口。还提出，二聚体或四聚体络合物中的单数单体充当活性通道，从而使相关的低聚作用。已经提出了具有不同功能行为的通道的二合一形式（“背对背”和“前到前”二聚体），尽管这是体内状态是未知的。