関連する実験動画
Updated: Jul 21, 2026
08:04
Assembling Molecular Shuttles Powered by Reversibly Attached Kinesins
Published on: January 26, 2019
DNA上でのモータータンパク質の繰り返しシャットリング
Sua Myong1, Ivan Rasnik, Chirlmin Joo
1Physics Department, University of Illinois, Urbana-Champaign, Urbana, Illinois 61801, USA.
Nature
|October 28, 2005
まとめ
エシェリキア・コライ・レプヘリケーゼは, DNA シャトル行為のユニークな繰り返しを示す. このメカニズムは,停滞した複製フォークで有毒な再結合中間物質を防止し,ゲノムの安定性を維持することができます.
科学分野:
- 分子生物学は分子生物学である.
- 遺伝学 遺伝学とは
- バイオケミストリー バイオケミストリー
背景:
- DNAヘリカーゼは,ゲノム安定性にとって重要なプロセスである再結合を調節する.
- 機能不全のヘリカーゼは,がんを含むヒトの病気と関連しています.
- ヘリコースメカニズムを理解することは,ゲノム不安定性の解読に不可欠です.
研究 の 目的:
- Srs2.2の同型であるEscherichia coli RepヘリケーゼのDNA結合および転位機構を調査する.
- 停滞した複製フォークにおけるRepヘリケーゼ活動の機能的影響を解明する.
主な方法:
- DNAの結合と転位を視覚化するための単分子光測定法を開発した.
- 単一鎖DNA (ssDNA) と相互作用する個々のRepモノマーが観察されました.
- DNAのブロックと停止した複製フォークの存在におけるレプリカの行動を研究した.
主要な成果:
- Repモノマーは,ATPの水解によって3'から5'の方向でssDNAに転位する.
- ブロックに遭遇すると,Repは,転位とスナップバックを含む繰り返しシャトリングを受けます.
- この反復的なシャトリングは,潜在的にDNAループを形成し,停滞した複製フォークの類型で観察され,ReCAフィラメント形成が遅れた.
結論:
- レプヘリケーゼは,DNAのブロックに反応して,新しい繰り返しシャトルメカニズムを示しています.
- この活動は,停止した複製フォークで有毒な再結合中間物質の形成を防ぐ可能性があります.
- Repヘリケーゼの作用は,ssDNA構造を管理することによって,ゲノムの完全性を維持するのに寄与する.
関連する概念動画
01:58Mechanical Protein Functions
Proteins perform many mechanical functions in a cell. These proteins can be classified into two general categories- proteins that generate mechanical forces and proteins that are subjected to mechanical forces. Proteins providing mechanical support to the structure of the cell, such as keratin, are subjected to mechanical force, whereas proteins involved in cell movement and transport of molecules across cell membranes, such as an ion pump, are examples of generating mechanical force.
02:54Nucleosome Remodeling
Nucleosomes are the basic units of chromatin compaction. Each nucleosome consists of the DNA bound tightly around a histone core, which makes the DNA inaccessible to DNA binding proteins such as DNA polymerase and RNA polymerase. Hence, the fundamental problem is to ensure access to DNA when appropriate, despite the compact and protective chromatin structure.
Nucleosome remodeling complex
Eukaryotic cells have specialized enzymes called ATP-dependent nucleosome remodeling enzymes. These enzymes...
Nucleosome remodeling complex
Eukaryotic cells have specialized enzymes called ATP-dependent nucleosome remodeling enzymes. These enzymes...
00:55DNA 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...
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...
02:37Restarting Stalled Replication Forks
DNA replication is initiated at sites containing predefined DNA sequences known as origins of replication. DNA is unwound at these sites by the minichromosome maintenance (MCM) helicase and other factors such as Cdc45 and the associated GINS complex.The unwound single strands are protected by replication protein A (RPA) until DNA polymerase starts synthesizing DNA at the 5’ end of the strand in the same direction as the replication fork. To prevent the replication fork from falling apart, a...
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...