電子移転パートナーであるサイトクロームc過酸化酵素とサイトクロームcの複合体の結晶構造
1Department of Chemistry, University of California, San Diego, La Jolla 92093-0317.
まとめ
研究者らは,酵母シトクロームcペロキシダースと酵母イソ-1-シトクロームcが複合した結晶構造を決定した.これは,特定のアミノ酸残基とヘム群を含む新しい電子伝送経路を明らかにした.
科学分野:
- バイオケミストリー バイオケミストリー
- 構造生物学 構造生物学とは
- バイオフィジックス 生物物理学
背景:
- サイトクロームc過酸化酵素 (CCP) とサイトクロームc (cytc) は,細胞呼吸における重要な酸化還元パートナーである.
- 彼らの相互作用を理解することは,電子伝送機構を明らかにする鍵です.
- 以前の電子伝送経路のモデルには,詳細な構造的証拠が欠けていました.
研究 の 目的:
- 酵母 CCP-酵母 iso-1-cyt c 複合体の高解像度結晶構造を決定する.
- これらのタンパク質間の電子伝送経路の構造的基礎を解明する.
- CCPの同類 (酵母) と異種 (馬) サイトとの相互作用を比較する c.
主な方法:
- X線結晶学を用いて,2つの異なるタンパク質複合体の3D構造を決定した.
- 高解像度構造データ (2.3 Å,2.8 Å) が複合体について得られた.
- 構造分析は,ヘム群と周囲のアミノ酸残基の空間的配置に焦点を当てました.
主要な成果:
- 酵母 CCP-酵母 iso-1-cyt c 複合体の結晶構造は,新しい,直接の電子転送経路を明らかにしました.
- この経路は,CPCの骨幹に特定の残留物 (Ala194,Ala193,Gly192,Trp191) を含んでおり,Van der WaalsのTrp191はCPCと接触しています.
- 酵母CCP-馬心細胞複合体の構造は,結晶化条件が異なるにもかかわらず,酵母-酵母複合体と顕著な類似性を示しました.
結論:
- 決定された構造は,CCPとcytcの間の電子移転の分子機構に関する前例のない洞察を提供します.
- この発見は,サイトクロームcとそのリドックスパートナーの間の非常に特殊な結合インターフェースと相互作用モードを示唆しています.
- この特異性は,異なる種のサイトクロームcに保たれ,進化的に保たれた相互作用を強調しています.
さらに関連する動画
08:04A New Approach for the Comparative Analysis of Multiprotein Complexes Based on 15N Metabolic Labeling and Quantitative Mass Spectrometry
Published on: March 13, 2014
08:37Analyzing Supercomplexes of the Mitochondrial Electron Transport Chain with Native Electrophoresis, In-gel Assays, and Electroelution
Published on: June 1, 2017
関連する概念動画
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...
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...
The Electron Transport Chain
The electron transport chain or oxidative phosphorylation is an exothermic process in which free energy released during electron transfer reactions is coupled to ATP synthesis. This process is a significant source of energy in aerobic cells, and therefore inhibitors of the electron transport chain can be detrimental to the cell's metabolic processes.
Inhibitors of the electron transport chain
Rotenone, a widely used pesticide, prevents electron transfer from Fe-S cluster to ubiquinone or Q in...
Inhibitors of the electron transport chain
Rotenone, a widely used pesticide, prevents electron transfer from Fe-S cluster to ubiquinone or Q in...
The Supercomplexes in the Crista Membrane
The mitochondrial cristae membrane is the primary site for the oxidative phosphorylation (OXPHOS) process of energy conversion mediated through respiratory complexes I to V. These complexes have been widely studied for decades, and it has been proven that they form supramolecular structures called respiratory supercomplexes (SC). These higher-order complexes may be crucial in maintaining the biochemical structure and improving the physiological activity of the individual complexes while...
Electron Transport Chain: Complex III and IV
During the electron transport chain, electrons from NADH and FADH2 are first transferred to complexes I and II, respectively. These two complexes then transfer the electrons to ubiquinol, which carries them further to complex III. Complex III passes the electrons across the intermembrane space to Cyt c, which carries them further to complex IV. Complex IV donates electrons to oxygen and reduces it to water. As electrons pass through complexes I, III, and IV, the energy released aids the pumping...
Electron Transport Chain Components
The electron transport chain (ETC) is a crucial metabolic pathway that facilitates energy conversion in prokaryotic and eukaryotic cells. In eukaryotes, the ETC comprises four membrane-associated protein complexes in the inner mitochondrial membrane. In prokaryotes, the ETC in the plasma membrane can vary in composition, with fewer or different complexes depending on the organism and environmental conditions. These complexes transfer electrons from electron donors, such as NADH and FADH2, to...
