高級ユカリオットのフェリチンのフェロキシダース部位に関する構造的な洞察
Ivano Bertini1, Daniela Lalli, Stefano Mangani
1Magnetic Resonance Center (CERM), University of Florence, 50019 Sesto Fiorentino, Florence, Italy. ivanobertini@cerm.unifi.it
Journal of the American Chemical Society
|March 20, 2012
まとめ
この研究は,より高い真核フェリチンの異なる種の最初の構造的識別を明らかにし,フェロキシダース活性部位における鉄と銅イオン協調を詳細に説明しています. これはフェリチニンに関する重要な洞察を提供します.
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
- バイオミネラライゼーション
背景:
- フェリチンは,そのフェロキシダース活性部位での酸化を通じて,鉄のバイオミネラル化を媒介する.
- 鉄酸化の構造的中間物質を理解することは,フェリチンのメカニズムを解明するために極めて重要です.
研究 の 目的:
- 金属含有フェリチンの構造を決定し,特にフェロキシダース活性部位の異なる種に焦点を当てました.
- フェリチンの鉄と銅の添加物の構造特性を比較する.
主な方法:
- 鉄 (FeSO4) と銅 (CuSO4) の溶液に浸されたカエルのフェリチン結晶の高解像度構造を取得するために,X線結晶学を使用しました.
- 異常差のフーリエ図は,金属イオンの位置と協調環境を特定するために使用されました.
主要な成果:
- マイクロオキソ/ヒドロキソブリッジ (Fe-Fe距離 ~3.1 Å) を有する異なる種の最初の構造的証拠は,より高い真核生物のフェリチンに観察されました.
- 銅の結合により,His54.4を含む鉄と比較して,明確な協調性と金属間距離 (~4.3 Å) の増加を伴う二銅 (II) センターが明らかになった.
- 急速浸漬実験では,一時的な二鉄種を捕獲し,提案された触媒機構を支持しました.
結論:
- 特定された異なる種とその調整は,より高いエウカリオートからフェリチンの鉄酸化機構のための重要な構造情報を提供します.
- 銅の独特の構造的振る舞いは,フェロキシダース部位における二価イオン相互作用の特異的な特徴を示唆しています.
- これらの発見は,鉄の吸収,酸化,貯蔵におけるフェリチンの役割の理解を進めています.
関連する概念動画
Conserved Binding Sites
Many proteins’ biological role depends on their interactions with their ligands, small molecules that bind to specific locations on the protein known as ligand-binding sites. Ligand-binding sites are often conserved among homologous proteins as these sites are critical for protein function.
Binding sites are often located in large pockets, and if their location on a protein’s surface is unknown, it can be predicted using various approaches. The energetic method computationally analyses the...
Binding sites are often located in large pockets, and if their location on a protein’s surface is unknown, it can be predicted using various approaches. The energetic method computationally analyses the...
Ligand Binding and Linkage
Allosteric proteins have more than one ligand binding site; the binding of a ligand to any of these sites influences the binding of ligands to the other sites. When a protein is allosteric, its binding sites are called coupled or linked. In the case of enzymes, the site that binds to the substrate is known as the active site and the other site is known as the regulatory site. When a ligand binds to the regulatory site, this leads to conformational changes in the protein that can influence the...
The Early Endosome: Endocytosis of Transferrin
Essential proteins such as insulin or low-density lipoprotein (LDL) and micronutrients such as iron enter a eukaryotic cell through receptor-mediated endocytosis. Subsequently, the early endosomes fuse with the vesicles containing such receptor-ligand complexes and play a vital role in sorting the incoming ligands and receptors. While the ligands are either degraded inside the vesicle or released into the cytosol, their receptors are returned to the plasma membrane for further rounds of...
Gene Families
Gene families consist of groups of genes proposed to have originated from a common ancestor. Typically these arise through events in which a gene or genes are mistakenly duplicated during cell division. Unlike their parent genes (which are subject to selection pressure to maintain function), these gene copies do not need to preserve their sequences and may evolve at a relatively faster rate.
Occasionally these regions can be adapted to take on new roles within the organism, becoming novel genes...
Occasionally these regions can be adapted to take on new roles within the organism, becoming novel genes...
Allosteric Proteins-ATCase
Binding sites linkages can regulate a protein's function. For example, enzyme activity is often regulated through a feedback mechanism where the end product of the biochemical process serves as an inhibitor.
Aspartate transcarbamoylase (ATCase) is a cytosolic enzyme that catalyzes the condensation of L-aspartate and carbamoyl phosphate to N-carbamoyl-L-aspartate. This reaction is the first step in pyrimidine biosynthesis. UTP and CTP, the end products of the pyrimidine synthesis pathway,...
Aspartate transcarbamoylase (ATCase) is a cytosolic enzyme that catalyzes the condensation of L-aspartate and carbamoyl phosphate to N-carbamoyl-L-aspartate. This reaction is the first step in pyrimidine biosynthesis. UTP and CTP, the end products of the pyrimidine synthesis pathway,...
Microbes and Other Elemental Cycles
Microbial activity plays a pivotal role in the biogeochemical cycling of iron and manganese, especially at the redox gradients characteristic of stratified aquatic environments. These cycles are driven by microbial transformations between oxidized and reduced forms of the metals, allowing organisms to exploit them for metabolic energy and structural purposes.Iron Cycling Across Redox GradientsIn neutral, oxygen-rich surface waters, iron is predominantly found in its oxidized, insoluble ferric...


![Protein Film Infrared Electrochemistry Demonstrated for Study of H2 Oxidation by a [NiFe] Hydrogenase](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2FCDNSource%2Fteasers%2F55858.jpg&w=3840&q=50)