関連する実験動画
Updated: Jul 28, 2026

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Analyzing and Building Nucleic Acid Structures with 3DNA
Published on: April 26, 2013
DNAトポイソメラーゼIIの構造とメカニズム
J M Berger1, S J Gamblin, S C Harrison
1Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts 02138, USA.
Nature
|January 18, 1996
まとめ
ハート型の酵素である酵母II型DNAトポイソメラーゼは,ATP調節されたクランプとして作用します. このクランプ構造により,中央チャネルを通してDNAを結合して輸送し,DNA複製と修復プロセスを促進します.
科学分野:
- バイオケミストリー バイオケミストリー
- 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.
背景:
- DNAトポイソメラーゼは,DNAトポロジーを管理する必須酵素である.
- II型DNAトポイソメラーゼは,DNA複製,転写,再結合において重要な役割を果たしています.
- 彼らの機能の構造的基礎を理解することは,治療戦略の開発の鍵です.
研究 の 目的:
- 酵母II型DNAトポイソメラーゼの分子構造を解明する.
- 酵素のDNA結合および輸送機構の構造モデルを提供すること.
主な方法:
- イーストII型DNAトポイソメラーゼの大きな断片のX線結晶学.
主要な成果:
- 結晶構造は,中央の孔を持つ心臓の形状の二重タンパク質を明らかにします.
- 分子モデルは,酵素を2つの異なるのセットを持つATP調節されたクランプとして描いています.
- この構造は,酵素がDNA複合体をどのように結合し,輸送し,放出するかを説明します.
結論:
- 明らかにされたクランプのような構造は,II型DNAトポイソメラーゼの機能に関する機械的洞察を提供します.
- この構造情報は,真核生物のDNA管理を理解するために極めて重要です.
- このモデルは,酵素調節と薬物設計に関するさらなる研究のための基盤を提供します.
関連する概念動画
The DNA Helix
Overview
DNA Helicases
DNA unwinding helicase enzymes are a type of motor protein. Motor proteins can translocate along filaments or polymers using energy generated from ATP hydrolysis. Helicases are involved in all the important cellular processes where DNA unwinding is required, such as DNA replication, repair, recombination, and transcription. They are present in all living organisms, but vary in their structure, function, and mechanism of action. For example, in prokaryotes, DnaB helicase binds and translocates...
DNA Topoisomerases
Topoisomerases are enzymes that relax overwound DNA molecules during various cell processes, including DNA replication and transcription. These enzymes regulate positive and negative DNA supercoiling without changing the nucleotide sequence. DNA overwinding in a clockwise direction results in positively supercoiled DNA, whereas underwinding in a counterclockwise direction produces negatively supercoiled DNA.
Types and Mechanism of action
Topoisomerases are divided into two main types. Type I...
Types and Mechanism of action
Topoisomerases are divided into two main types. Type I...
Single-Strand DNA Binding Proteins
For successful DNA replication, the unwinding of double-stranded DNA must be accompanied by stabilization and protection of the separated single strands of the DNA. This crucial task is performed by single-strand DNA-binding (SSB) proteins. They bind to the DNA in a sequence-independent manner, which means that the nitrogenous bases of the DNA need not be present in a specific order for binding of SSB proteins to it. The binding of SSB proteins straightens single-stranded DNA (ssDNA) and makes...
The 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...
Inhibitors of Bacterial DNA Synthesis
Bacterial pathogens depend on precise and efficient DNA replication to sustain infection. Two type II topoisomerases—DNA gyrase and topoisomerase IV—are critical to this process, as they resolve DNA supercoiling and unlink chromosomes during replication. Fluoroquinolones, synthetic derivatives of quinolones, exploit this mechanism by stabilizing the transient DNA–enzyme cleavage complex, preventing strand religation, and causing lethal double-strand breaks. These antibiotics are selectively...

