ナノディスクにおけるシトクロームP450 3A4からの基板解離に対するアロステリック効果は,アンサンブルおよび単分子光スペクトロスコーピーによって観察された
Abhinav Nath1, Peter K Koo, Elizabeth Rhoades
1Department of Medicinal Chemistry, University of Washington, Seattle, Washington, USA.
Journal of the American Chemical Society
|November 5, 2008
まとめ
単一分子光の研究は,エフェクタがサイトクロームP450 (CYP) 3A4酵素の運動にどのように影響するかを明らかにしています. エフェクターは,基板の放出を遅らせ,薬物の代謝を潜在的に強化することができます.
科学分野:
- バイオケミストリー バイオケミストリー
- 酵素学 酵素学とは
- 薬理学 薬理学とは
背景:
- サイトクロームP450 (CYP) 3A4は,ヒトにおける重要な薬物代謝酵素である.
- CYP3A4は,基質とエフェクターの複数の結合部位により,複雑なアロステル運動性を表している.
研究 の 目的:
- シングル分子光を用いてCYP3A4のアロステリックメカニズムを調査する.
- CYP3A4.4におけるナイル紅染料の在留時間を測定するために,アルファナフトホフラボンの効果を測定する.
主な方法:
- 全内反射光顕微鏡を用いた.
- CYP3A4.4を組み込むために,表面固定された脂質ナノディスクを使用しました.
- 光染料の単分子滞在時間を測定した.ナイルレッド.
主要な成果:
- CYP3A4エフェクターが基質オフレートを低下させることが実証されました.
- 酵素運動のエフェクター調節の直接的証拠を提供した.
- アルファナフトフラボンの存在で,ナイル紅の滞在時間の変化が観察されました.
結論:
- 単一分子の方法は,CYPのアロステリックメカニズムに関する強力な洞察を提供します.
- サブストラットオフレートの低下は,エフェクター強化代謝の潜在的なメカニズムを示します.
- この発見は,薬物の代謝と酵素調節の理解に寄与する.
関連する概念動画
Allosteric Regulation
Allosteric regulation of enzymes occurs when the binding of an effector molecule to a site that is different from the active site causes a change in the enzymatic activity. This alternate site is called an allosteric site, and an enzyme can contain more than one of these sites. Allosteric regulation can either be positive or negative, resulting in an increase or decrease in enzyme activity. Most enzymes that display allosteric regulation are metabolic enzymes involved in the degradation or...
Cooperative Allosteric Transitions
Cooperative allosteric transitions can occur in multimeric proteins, where each subunit of the protein has its own ligand-binding site. When a ligand binds to any of these subunits, it triggers a conformational change that affects the binding sites in the other subunits; this can change the affinity of the other sites for their respective ligands. The ability of the protein to change the shape of its binding site is attributed to the presence of a mix of flexible and stable segments in the...
Cooperative Allosteric Transitions
Cooperative allosteric transitions can occur in multimeric proteins, where each subunit of the protein has its own ligand-binding site. When a ligand binds to any of these subunits, it triggers a conformational change that affects the binding sites in the other subunits; this can change the affinity of the other sites for their respective ligands. The ability of the protein to change the shape of its binding site is attributed to the presence of a mix of flexible and stable segments in the...
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,...
Enzyme Inhibition
Inhibitors are molecules that reduce enzyme activity by binding to the enzyme. In a normally functioning cell, enzymes are regulated by a variety of inhibitors. Drugs and other toxins can also inhibit enzymes. Some inhibitors bind to the enzyme’s active site, while others inhibit enzymatic activity by binding to other sites on the protein structure.
Protein Dynamics in Living Cells
Different fluorescence-based techniques are used to study the protein dynamics in living cells. These techniques include FRAP, FRET, and PET.
Fluorescent recovery after photobleaching (FRAP) is a fluorescent-protein-based detection technique used to quantify protein movement rates within the cell. This method exposes a small portion of the cell to an intense laser beam. The laser beam causes permanent photobleaching of the fluorophore-tagged proteins in the exposed region. As the bleached...
Fluorescent recovery after photobleaching (FRAP) is a fluorescent-protein-based detection technique used to quantify protein movement rates within the cell. This method exposes a small portion of the cell to an intense laser beam. The laser beam causes permanent photobleaching of the fluorophore-tagged proteins in the exposed region. As the bleached...


