ヒトインドレアミン2,3ダイオキシゲネーゼ1の抑制メカニズム
Ariel Lewis-Ballester1, Shay Karkashon1, Dipanwita Batabyal
1Department of Physiology and Biophysics , Albert Einstein College of Medicine , Bronx , New York 10461 , United States.
Journal of the American Chemical Society
|June 14, 2018
まとめ
ヒューマンインドレアミン2,3-二酸化酵素1 (hIDO1) とトリプトファン二酸化酵素 (hTDO) は,構造的に類似しているが,抑制結合部位では異なっている. 研究者らは,トリプトファンまたは変異によってこの部位を遮断すると,hIDO1の活性が抑制され,3インドルエタノール (IDE) によって逆転することがわかった.
科学分野:
- 生物化学
- 酵素学
- 構造生物学
背景:
- ヒューマンインドレアミン2,3-二酸化酵素1 (hIDO1) とトリプトファン二酸化酵素 (hTDO) は,構造的に類似した酵素で,トリプトファン (Trp) からN-ホルミルキヌレニン (NFK) に変換する.
- hIDO1には独特の抑制性基板結合部位 (Si) があり,hTDOにはないが,トリプトファン結合の相互作用が顕著である.
研究 の 目的:
- hIDO1 Si部位とS167H変異の結合が酵素活性に及ぼす機能的影響を調査する.
- 3-インドールエタノール (IDE) が抑制されたhIDO1活動を回復させるメカニズムを解明する.
主な方法:
- 代謝活動と基質/リガンド結合率を分析するために,酵素運動の研究が行われました.
- 特定の残留物の役割を調べるために,サイト指向型変異 (S167H) が使用された.
- トリプトファンとIDEがhIDO1活動に及ぼす影響の特徴
主要な成果:
- トリプトファンがSi部位またはS167H変異に結合すると,hIDO1の周回活動が著しく遅れます.
- IDEは,SiへのTrp結合を防ぐか,リガンドトンネルを再開することによって,抑制されたhIDO1活動を効果的に救済します.
- S167H変異は酸素結合率を劇的に低下させ,リガンドトンネルの阻害を示唆する.
結論:
- hIDO1のユニークなSi部位とS167残基は,その触媒的活性を調節する上で重要な役割を果たします.
- IDEは効果体として作用し,Si部位との相互作用によってhIDO1の活性を調節する.
- これらの発見は,hIDO1選択性阻害剤の構造ベースの設計のための洞察を提供します.
関連する概念動画
SN1 Reaction: Mechanism
14.4K
Kinetic studies of ionization of a tertiary halide in a protic solvent suggest that only the substrate participates in the rate-determining step (slow step). The nucleophile is involved only after the slowest step. The SN1 reaction takes place in a multiple-step mechanism.
Firstly, the haloalkane ionizes to generate a carbocation intermediate and a halide ion. This heterolytic cleavage is highly endothermic with large activation energy. The ionization of the substrate, facilitated by a...
Firstly, the haloalkane ionizes to generate a carbocation intermediate and a halide ion. This heterolytic cleavage is highly endothermic with large activation energy. The ionization of the substrate, facilitated by a...
14.4K
Feedback Inhibition
57.2K
Biochemical reactions are occurring constantly in cells, converting starting substances to different products, usually with the help of enzymes that speed the reactions. Without enzymes, it would take far too long for most reactions to occur to be useful to the cell!
57.2K
Preparation of 1° Amines: Hofmann and Curtius Rearrangement Mechanism
4.1K
The Hofmann and Curtius rearrangement reactions can be applied to synthesize primary amines from carboxylic acid derivatives such as amides and acyl azides. In the Hofmann rearrangement, a primary amide undergoes deprotonation in the presence of a base, followed by halogenation to generate an N-haloamide. A second proton abstraction produces a stabilized anionic species, which rearranges to an isocyanate intermediate via an alkyl group migration from the carbonyl carbon to the neighboring...
4.1K
1° Amines to Diazonium or Aryldiazonium Salts: Diazotization with NaNO2 Mechanism
5.0K
Nitrous acid is a relatively weak and unstable acid prepared in situ by the reaction of sodium nitrite and cold, dilute hydrochloric acid. In an acidic solution, the nitrous acid undergoes protonation when it loses water to form a nitrosonium ion—an electrophile. Nitrous acid reacts with primary amines to give diazonium salts. The reaction is called diazotization of primary amines.
5.0K
Enzyme Inhibition
92.6K
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.
92.6K
Inhibition of Cdk Activity
6.0K
The orderly progression of the cell cycle depends on the activation of Cdk protein by binding to its cyclin partner. However, the cell cycle must be restricted when undergoing abnormal changes. Most cancers correlate to the deregulated cell cycle, and since Cdks are a central component of the cell cycle, Cdk inhibitors are extensively studied to develop anticancer agents. For instance, cyclin D associates with several Cdks, such as Cdk 4/6, to form an active complex. The cyclin D-Cdk4/6 complex...
6.0K


