Assembly of a Multimeric Membrane Protein Complex

多聚膜蛋白复合物的组装

• 批准号: 8817373
• 负责人: Steven Theg
• 金额: $ 25.86万
• 依托单位: University of California-Davis
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1989
• 资助国家: 美国
• 起止时间: 1989-04-15 至 1994-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=8817373&HistoricalAwards=false
• 关键词: Assembly; Multimeric; Membrane; Protein; Complex

Many enzymes and structural proteins are multimeric complexes made up of a number of identical or different subunits. For those complexes located within sub-cellular organelles, assembly often does not proceed until the cytoplasmically synthesized subunits are translocated into the organelle. The photosynthetic oxygen-evolving enzyme complex (OEC) of chloroplasts is one such complex which is minimally composed of three nuclear-encoded polypeptides in association with five chloroplast-encoded subunits. This project focuses on the assembly of the OEC in organello by presenting the three nuclear-encoded subunits, synthesized in vitro from cloned genes, to isolated intact chloroplasts. The investigation will proceed in two sequential phases. In the first, the experimental conditions allowing the efficient association of the three extrinsic subunits with PS II will be optimized, and the state of the newly assembled OEC will be evaluated. Different conditions will be examined for their ability to produce newly assembled complexes which most closely resemble those formed in vivo. In the second phase, some of the mechanistic details concerning OEC assembly will be elucidated, such as the presence of pools of unassembled subunits within the chloroplasts, the requirement for de novo synthesis of chloroplast-encoded PS II reaction center proteins, and the lifetimes of unassembled subunits in the lumen. Where possible, these results will be used to evaluate general models of protein complex assembly, and the regulation and control thereof. The living cell contains complex machinery for many of its functions. These complex assemblages are made up of components (proteins) which are made in different compartments of the cell. The process by which these are made, transported and assembled serves to control the cell's metabolism. This project studies a complex of photosynthesis but the general principles being elucidated apply to many cell processes.

许多酶和结构蛋白是多聚体复合物 由许多相同或不同的亚单位组成。 为 这些复合物位于亚细胞器内， 通常在细胞质合成 亚基被转移到细胞器中。 光合 叶绿体的放氧酶复合体（OEC）就是这样一种 复合体，其最低限度由三个核编码的 与五种叶绿体编码的 亚单位。 该项目的重点是组装OEC， 通过呈递三个核编码的亚基， 从克隆基因体外合成，到分离完整的 叶绿体 调查将分两个阶段进行 阶段。 首先，实验条件允许 三个外源亚基与PS II的有效结合 将得到优化，新组装的OEC的状态将 被评价。 不同的条件将被检查， 能够产生新组装的复合物， 与体内形成的类似。 在第二阶段， 将阐明关于OEC组装的机械细节， 例如细胞内存在未组装的亚基池 叶绿体，从头合成的要求， 叶绿体编码的PS II反应中心蛋白， 管腔中未组装亚基的寿命。 在可能的情况下， 这些结果将用于评估蛋白质的一般模型， 复杂的组件及其调节和控制。 活细胞包含复杂的机制， 功能协调发展的 这些复杂的装配体由组件组成 （蛋白质）在细胞的不同区域产生。 制造、运输和组装这些物品的过程 用来控制细胞的新陈代谢 该项目研究了 光合作用的复杂性，但一般原则是 阐明的适用于许多细胞过程。