関連する実験動画
Updated: Jun 5, 2026

09:43
Measurement of Heme Synthesis Levels in Mammalian Cells
Published on: July 9, 2015
ヘムを強烈に結合するグアナインに富んだRNAとDNAは,酸素伝達反応を触媒化する
Lester C-H Poon1, Stephen P Methot, William Morabi-Pazooki
1Department of Molecular Biology & Biochemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada.
Journal of the American Chemical Society
|January 27, 2011
まとめ
グアニンに富んだ核酸がヘムと複合すると,酸化反応を触媒化し,過酸化水素から酸素を様々な基質に転送します. このヘムに依存した酸素伝搬は,生命の初期段階や病気を理解し,新たな治療法を開発する上で重要な意味を持つ.
科学分野:
- バイオケミストリー バイオケミストリー
- 分子生物学は分子生物学である.
- カタリシス カタリシス カタリシス
背景:
- RNAとDNAを含むグアナインに富んだ核酸は,G-四重複構造を形成する.
- これらのG四重複構造はFe (III) ヘムと緊密に結合し,触媒的可能性を持つ複合体を形成します.
研究 の 目的:
- 多種多様なG-四重複合体-ヘム複合体の触媒活性を調査する.
- ヘム媒介の酸化反応におけるメカニズムと酸素源を決定する.
主な方法:
- Fe(III) ヘムで複合された様々なグアニンに富んだRNAとDNAのG四重複合体を利用した.
- 酸素の移転を追跡するために,18Oラベル付きの過酸化水素を使用した.
- ハメット分析を含む基板酸化に関する運動学的研究を行った.
- G-四重複構造とのヘム相互作用をモデル化するために分子ドッキングを使用しました.
主要な成果:
- G-クアドルプレックス-ヘム複合体は,チオアニゾール,インドール,スタイレンの2電子酸化を強力に触媒化する.
- 基板に転送される酸素は,ヘムの活性化フェリル部分から発生します.
- チオアニゾール酸化の運動分析では,直接の酸素転送と酸素リバウンドメカニズムを区別することができなかった.
- インドール酸化により,インディゴ色素を含む様々な製品が得られました.
- 構造モデリングは,これらのリボ酵素とデオキシリボ酵素の比較的オープンな活性部位を示唆しました.
結論:
- ヘム結合のG四重複素は,酸素伝達反応の効果的な触媒である.
- この触媒能力は,生命の起源,酵素の設計,および医学的な応用について幅広い意味を持つ.
- 核酸におけるヘム依存触媒に関するさらなる研究は,細胞の酸化性疾患と癌の治療法に影響を与える可能性があります.
関連する概念動画
Oxygen Transport in the Blood
Hemoglobin (Hb) is a crucial molecule in the human body, consisting of four polypeptide chains, each bound to an iron-containing heme group. This unique structure enables hemoglobin to bind to oxygen, with each molecule capable of combining with four molecules of oxygen, leading to rapid and reversible oxygen loading. When fully loaded with oxygen, it is called oxyhemoglobin, while hemoglobin that has released oxygen is called reduced hemoglobin or deoxyhemoglobin. As hemoglobin binds oxygen,...
Hemoglobin
Hemoglobin is a globular protein made up of four subunits. Two of these subunits are alpha chains, and the other two are beta chains. Each subunit contains a molecule of heme, which has an iron atom and can bind to oxygen. When an oxygen molecule binds to one heme group, it changes the shape of hemoglobin, making it easier for the other heme groups to bind oxygen as well.
When all four heme groups are bound to oxygen, the resulting molecule is called oxyhemoglobin. As a result, arterial blood...
When all four heme groups are bound to oxygen, the resulting molecule is called oxyhemoglobin. As a result, arterial blood...
Cooperative Binding of Transcription Regulators
Transcriptional regulators bind to specific cis-regulatory sequences in the DNA to regulate gene transcription. These cis-regulatory sequences are very short, usually less than ten nucleotide pairs in length. The short length means that there is a high probability of the exact same sequence randomly occurring throughout the genome. Since regulators can also bind to groups of similar sequences, this further increases the chances of random binding. Transcriptional regulators form dimers that...
Cooperative Binding of Transcription Regulators
Transcriptional regulators bind to specific cis-regulatory sequences in the DNA to regulate gene transcription. These cis-regulatory sequences are very short, usually less than ten nucleotide pairs in length. The short length means that there is a high probability of the exact same sequence randomly occurring throughout the genome. Since regulators can also bind to groups of similar sequences, this further increases the chances of random binding. Transcriptional regulators form dimers that...
Riboswitches
Riboswitches are non-coding mRNA domains that regulate the transcription and translation of downstream genes without the help of proteins. Riboswitches bind directly to a metabolite and can form unique stem-loop or hairpin structures in response to the amount of the metabolite present. They have two distinct regions – a metabolite-binding aptamer and an expression platform.
The aptamer has high specificity for a particular metabolite which allows riboswitches to specifically regulate...
The aptamer has high specificity for a particular metabolite which allows riboswitches to specifically regulate...
Ribozymes
The term ribozyme is used for RNA that can act as an enzyme. Ribozymes are mainly found in selected viruses, bacteria, plant organelles, and lower eukaryotes. Ribozymes were first discovered in 1982 when Tom Cech’s laboratory observed Group I introns acting as enzymes. This was shortly followed by the discovery of another ribozyme, Ribonulcease P, by Sid Altman’s laboratory. Both Cech and Altman received the Nobel Prize in chemistry in 1989 for their work on ribozymes.
Ribozymes can be...
Ribozymes can be...

