ポリアミド−インターカレーター結合体によるタンパク質−DNA複合体のアロステリック抑制
Eric J Fechter1, Peter B Dervan
1Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, USA.
Journal of the American Chemical Society
|July 10, 2003
まとめ
新しいヘアピンポリアミド-アクリジン結合体は,タンパク質-DNAの相互作用を阻害することによって,遺伝子転写を阻害します. これらの分子はDNAに特異的に結合し,その構造を変化させ,転写因子の結合を防ぐ.
科学分野:
- 分子生物学は分子生物学である.
- 化学生物学 化学生物学とは
- 遺伝学 遺伝学とは
背景:
- タンパク質-DNA相互作用のシーケンス固有の阻害は,遺伝子発現を化学的に調節する鍵です.
- ヘアピンポリアミドは,タンパク質-DNA複合体を阻害することができますが,その有効性は異なります.
- ポリアミドやbZip因子のようなメジャー・グルーブ結合タンパク質は,同じDNAマイナー・グルーブを占有することができる.
研究 の 目的:
- 新しいヘアピンポリアミド-アクリジン結合体を合成し,特徴づけること.
- これらの結合体のDNA結合親和性と配列特異性を調査する.
- これらの結合体が,特にGCN4 bZipタンパク質によるタンパク質-DNA結合を阻害できるかどうかを判断する.
主な方法:
- 4つのヘアピンポリアミド-アクリジン結合物の合成.
- 配列の親和性と特異性を決定するDNA結合測定法.
- アクリジンインターキャラを評価するためのDNA解き放つ測定.
- GCN4 bZipタンパク質とその標的DNA配列を用いた阻害アッセイ.
主要な成果:
- 合成されたポリアミド-アクリジン結合体は,高い親和性と配列特異性でDNAマイナー・グルーヴを結合する.
- これらの結合体はDNAの解き放たれ (14〜15度) を誘導し,アクリジンのインターカレーションを示します.
- コンジュガートは,GCN4 bZipタンパク質による主要な溝のDNA結合を効果的に阻害します.
結論:
- ポリアミド-アクリジン結合体は,シーケンス固有のマイナー・グリューブ結合と局所的なDNA解を組み合わせている.
- この二重メカニズムは,DNAにアロステリック構造変化を引き起こします.
- この類の分子は,タンパク質-DNA構造に関係なく,転写因子結合の一般的阻害体としての潜在性を示しています.
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...
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...
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 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...
Eukaryotic Transcription Inhibitors
Certain biochemical processes, such as embryonic development and cell growth regulation, depend on the repression of specific genes. DNA binding proteins known as eukaryotic transcription inhibitors regulate the repression of gene expression in eukaryotes. The presence of these inhibitors at the required location and time in the cell is triggered by the presence of hormones and additional signals from other cells.
Eukaryotic transcription inhibitors usually contain two distinct domains, a DNA...
Eukaryotic transcription inhibitors usually contain two distinct domains, a DNA...
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,...


