一个涉及生物能量和生物发生的线粒体蛋白质家族
U Schulte1, M Arretz, H Schneider
1Institut für Biochemie, Universität Düsseldorf, FRG
Nature
|May 11, 1989
概括
线粒体细胞染色体还原酶子单元I,一个没有氧化还原中心的大型蛋白质,对电子运输至关重要. 这项研究将I子单元与其他蛋白质组合在一起,揭示了它在减少酶组合和功能中的重要作用.
科学领域:
- 生物化学 生物化学
- 分子生物学分子生物学
- 细胞生物学 细胞生物学
背景情况:
- 线粒体呼吸链复合体涉及众多的子单元,而非还原中心子单元的功能在很大程度上是未知的.
- 在Neurospora crassa中,细胞染色体还原酶复合体有9个子单元,包括大型的外周膜蛋白I和II,缺少氧化还原中心.
研究的目的:
- 为了研究细胞染色体减少酶亚单元I的功能和分类.
- 了解非氧化还原中心子单元在线粒体呼吸链复杂组合和活动中的作用.
主要方法:
- 细胞染色体还原酶复合物的生物化学分化.
- 对具有特定线粒体加工酶 (MPP和PEP) 缺陷的酵母突变菌的分析.
- 细胞染色体减少酶子单元I的蛋白质家族分类.
主要成果:
- 一个缺乏I和II子单元的细胞染色体还原酶部分在电子转移中不活跃.
- 酵母酵母I或II子单元的基因缺陷破坏了减少酶组合.
- 细胞染色体减少酶的I子单元被确定为属于特定的蛋白质家族.
结论:
- 细胞染色体还原酶子单元I对于线粒体呼吸链的组装和活动至关重要.
- 亚单元I被归类为一种蛋白质家族,为其功能提供了洞察力.
- 了解这些子单位是理解线粒体生物能学的关键.
相关概念视频
Electron Transport Chains
The final stage of cellular respiration is oxidative phosphorylation that consists of two steps: the electron transport chain and chemiosmosis. The electron transport chain is a set of proteins found in the inner mitochondrial membrane in eukaryotic cells. Its primary function is to establish a proton gradient that can be used during chemiosmosis to produce ATP and generate electron carriers, such as NAD+ and FAD, that are used in glycolysis and the citric acid cycle.
The ETC is comprised of...
The ETC is comprised of...
The Inner Mitochondrial Membrane
The inner mitochondrial membrane is the primary site of ATP synthesis. The inner membrane domain that forms a smooth layer adjacent to the outer membrane is called the inner boundary membrane. This domain contains membrane transporters that drive metabolites in and out of the mitochondria. In contrast, the inner membrane network that invaginates into the matrix space is called the cristae membrane. This domain accounts for principle mitochondrial function as it accommodates the protein...
Electron Transport Chain: Complex I and II
The mitochondrial electron transport chain (ETC) is the main energy generation system in the eukaryotic cells. However, mitochondria also produce cytotoxic reactive oxygen species (ROS) due to the large electron flow during oxidative phosphorylation. While Complex I is one of the primary sources of superoxide radicals, ROS production by Complex II is uncommon and may only be observed in cancer cells with mutated complexes.
ROS generation is regulated and maintained at moderate levels necessary...
ROS generation is regulated and maintained at moderate levels necessary...
Mitochondrial Protein Sorting
Mitochondria are double-membrane organelles of the eukaryotes involved in cellular metabolism, signaling, ATP synthesis, and programmed cell death. Each of these processes requires specific proteins and enzymes that must be correctly sorted to the right mitochondrial subcompartment for the proper functioning of the organelle.
Most of these mitochondrial proteins are encoded by the nucleus and imported to the mitochondria as unfolded or loosely folded precursors. Mitochondrial precursors...
Most of these mitochondrial proteins are encoded by the nucleus and imported to the mitochondria as unfolded or loosely folded precursors. Mitochondrial precursors...
Translocation of Proteins into the Mitochondria
Mitochondrial precursors are translocated to the internal subcompartments via independent mechanisms involving distinct protein machineries called translocases.
Sorting of outer membrane proteins:
Mitochondrial outer membrane proteins are of two types: the transmembrane, beta-barrel porins, and the membrane-anchored, alpha-helical proteins. Beta-barrel porin precursors are translocated by the TOM complex and inserted into the outer mitochondrial membrane by the SAM complex. In contrast,...
Sorting of outer membrane proteins:
Mitochondrial outer membrane proteins are of two types: the transmembrane, beta-barrel porins, and the membrane-anchored, alpha-helical proteins. Beta-barrel porin precursors are translocated by the TOM complex and inserted into the outer mitochondrial membrane by the SAM complex. In contrast,...
Energy to Drive Translocation
Mitochondrial protein import is powered by two distinct energy sources: ATP hydrolysis and electrochemical potential across the inner membrane. Newly synthesized precursors are bound by cytosolic chaperones of the Hsp70 family, which guide them to the import receptors on the mitochondrial surface. Utilizing the energy of ATP hydrolysis, Hsp70 chaperones transfer these precursors to the TOM receptors on the mitochondrial outer membrane.
Generally, polypeptides are unfolded by two distinct...
Generally, polypeptides are unfolded by two distinct...


