関連する実験動画
Updated: Jul 19, 2026
11:42
Iterative Optimization of DNA Duplexes for Crystallization of SeqA-DNA Complexes
Published on: November 1, 2012
2.8Aのメットレプレッサー・オペレータ複合体の結晶構造は,β鎖によるDNA認識を明らかにする
1Department of Biochemistry and Molecular Biology, University of Leeds, UK.
Nature
|October 1, 1992
まとめ
メト・レプレッサータンパク質は,ベータリボンをメジャー・グルーヴに挿入してDNAを結合し,塩基対との水素結合を形成します. また,精密な配列認識のためにDNAの骨幹の柔軟性を検出します.
科学分野:
- 構造生物学 構造生物学とは
- 分子生物学は分子生物学である.
- 遺伝学 遺伝学とは
背景:
- メトレプレッサーは重要な転写調節体である.
- タンパク質とDNAの相互作用を理解することは,遺伝子調節にとって極めて重要です.
- 抑制剤の特定の結合メカニズムは,遺伝子発現制御を決定する.
研究 の 目的:
- メートリプレッサーとそのオペレータDNAの間の原子レベルの相互作用を解明する.
- メット・レプレッサー・オペレータ・コンプレックスにおけるシーケンス特異性の構造的基礎を決定する.
- 直接的な塩基対相互作用を超えた新しい認識メカニズムを調査する.
主な方法:
- X線結晶学を用いて,メット・レプレッサー・オペレータ複合体の3D構造を決定した.
- 詳細な構造分析は,タンパク質とDNAのインターフェースに焦点を当てた.
- 水素結合とDNA骨幹の相互作用の識別.
主要な成果:
- 2次元メット抑制剤分子は,18塩基対のDNA断片の隣接部位と結合する.
- アンチパラレルタンパク質ベータリボンは,B型DNAの主要な溝に挿入されます.
- 直接の水素結合は,抑制性アミノ酸とDNA塩基対の間に形成されます.
- Repressorは,配列に依存するDNA骨幹の歪みと柔軟性を認識します.
結論:
- メット・リプレッサーは,ベータ・リボン相互作用による直接の塩基対認識を通じてシーケンス特異性を達成する.
- DNAの骨格構造を感知するレプレッサーの能力は,特異性の追加層を提供します.
- この二重認識メカニズムは,ターゲットオペレータシーケンスの高精度結合を保証します.
関連する概念動画
01:16The DNA Helix
Overview
02:05DNA as a Genetic Template
Two structural features of the DNA molecule provide a basis for the mechanisms of heredity: the four nucleotide bases and its double-stranded nature. The Watson-Crick model of double-helical DNA structure, proposed in 1952, drew heavily upon the X-ray crystallography work of researchers Rosalind Franklin and Maurice Wilkins. Watson, Crick, and Wilkins jointly received the Nobel Prize in Physiology or Medicine for their work in 1962. Franklin was, controversially, excluded from the prize for...
03:01The Replisome
DNA replication is carried out by a large complex of proteins that act in a coordinated matter to achieve high-fidelity DNA replication. Together this complex is known as the DNA replication machinery or the replisome.
The synthesis of the leading and lagging strands is a highly coordinated process. To explain this, the “Trombone model” was proposed by Bruce Alberts in 1980. The DNA loop formation starts when a primer is synthesized on the parent lagging strand. The loop grows with the...
The synthesis of the leading and lagging strands is a highly coordinated process. To explain this, the “Trombone model” was proposed by Bruce Alberts in 1980. The DNA loop formation starts when a primer is synthesized on the parent lagging strand. The loop grows with the...
02:13Cooperative 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...
02:04Co-activators and Co-repressors
Gene transcription is regulated by the synergistic action of several proteins that form a complex at a gene regulatory site. This is observed in eukaryotes, where the regulation of gene expression is a complex process. Regulatory proteins in eukaryotes can broadly be classified into two types – regulators that bind directly to specific DNA sequences and co-regulators that associate with regulatory proteins but cannot directly bind to the DNA. These co-regulators are further divided into...
01:07The DNA Helix
Deoxyribonucleic acid, or DNA, is the genetic material responsible for passing traits from generation to generation in all organisms and most viruses. DNA is composed of two strands of nucleotides that wind around each other to form a spring-like structure called a double helix. However, the double helix is not perfectly symmetrical. Instead, there are regularly occurring grooves in the structure. The major groove occurs where the sugar-phosphate backbones are relatively far apart. This space...