細菌の免疫系からのRNA誘導監視複合体の構造
Blake Wiedenheft1,2, Gabriel C Lander3, Kaihong Zhou1,2
1Howard Hughes Medical Institute, University of California, Berkeley, California 94720, USA.
Nature
|September 23, 2011
まとめ
バクテリアは,外来DNAを統合することによって,ウイルスから防御するためにCRISPR-Casシステムを使用します. カスケード複合体は,CRISPR由来RNAs (crRNAs) によって導かれ,侵入した核酸を認識して結合し,破壊を開始します.
科学分野:
- 微生物学 微生物学とは
- 分子生物学は分子生物学である.
- 構造生物学 構造生物学とは
背景:
- バクテリアと古生物は,CRISPRロシオにDNAを統合することによって,ウイルスやプラズミドに対する耐性を発達させる.
- CRISPRのロシオは,外来DNAとの接触を記録し,防御のためにCRISPR由来RNA (crRNAs) を生成する.
- Escherichia coliでは,crRNAsはカスケード複合体の一部であり,細菌菌の保護に不可欠です.
研究 の 目的:
- CRISPR媒介抗ウイルス防御の構造的基礎を解明する.
- ターゲット結合前と後のカスケード複合体のサブナノメートル構造を決定する.
主な方法:
- カスケード複合体を視覚化するために,冷凍電子顕微鏡を用いた.
- Cascadeの無結合状態とターゲット結合状態の構造分析が行われました.
主要な成果:
- カスケード複合体は,タンパク質サブユニットに沿って表示されるcrRNAを持つ海馬形の構造を示しています.
- 構造は,crRNAの保護と塩基配列の可用性を明らかにします.
- 標的結合はカスケードにおける構造変化を誘導し,Cas3核酵素の採用を潜在的にシグナルする.
結論:
- 決定された構造は,CRISPR-Casの抗ウイルス防御のメカニズムについての洞察を提供します.
- Cascadeのアーキテクチャは,crRNAによる誘導による認識と,その後の外来核酸の破壊を容易にする.
関連する概念動画
Types of RNA
61.3K
Overview
Three main types of RNA are involved in protein synthesis: messenger RNA (mRNA), transfer RNA (tRNA), and ribosomal RNA (rRNA). These RNAs perform diverse functions and can be broadly classified as protein-coding or non-coding RNA. Non-coding RNAs play important roles in the regulation of gene expression in response to developmental and environmental changes. Non-coding RNAs in prokaryotes can be manipulated to develop more effective antibacterial drugs for human or animal use.
RNA...
Three main types of RNA are involved in protein synthesis: messenger RNA (mRNA), transfer RNA (tRNA), and ribosomal RNA (rRNA). These RNAs perform diverse functions and can be broadly classified as protein-coding or non-coding RNA. Non-coding RNAs play important roles in the regulation of gene expression in response to developmental and environmental changes. Non-coding RNAs in prokaryotes can be manipulated to develop more effective antibacterial drugs for human or animal use.
RNA...
61.3K
Bacterial RNA Polymerase
19.9K
Unlike eukaryotes, bacteria use a single RNA Polymerase (RNAP) to transcribe all genes. The different subunits of bacterial RNAPhave distinct functions. The multisubunit structure of the bacterial RNAP helps the enzyme to maintain catalytic function, facilitate assembly, interact with DNA and RNA, and self-regulate its activity.
In most genes, the transcription site is a single base present upstream of the coding sequence. Though RNAP is a catalytically efficient enzyme, it does not recognize...
In most genes, the transcription site is a single base present upstream of the coding sequence. Though RNAP is a catalytically efficient enzyme, it does not recognize...
19.9K
CRISPR and crRNAs
14.6K
Bacteria and archaea are susceptible to viral infections just like eukaryotes; therefore, they have developed a unique adaptive immune system to protect themselves. Clustered regularly interspaced short palindromic repeats and CRISPR-associated proteins (CRISPR-Cas) are present in more than 45% of known bacteria and 90% of known archaea.
The CRISPR-Cas system stores a copy of foreign DNA in the host genome and uses it to identify the foreign DNA upon reinfection. CRISPR-Cas has three different...
The CRISPR-Cas system stores a copy of foreign DNA in the host genome and uses it to identify the foreign DNA upon reinfection. CRISPR-Cas has three different...
14.6K
Intracellular Movement of Viruses and Bacteria
3.0K
Intracellular bacteria and viruses often comprise a group of highly infectious pathogens that can cause several diseases. Bacterial pathogens include those belonging to the genus Rickettsia responsible for conditions such as rocky mountain spotted fever and the Mediterranean spotted fever; Chlamydia, a genus responsible for a sexually transmitted disease; Coxiella burnetii, an agent responsible for Q fever. Viral pathogens include vaccinia—a poxvirus, and herpes simplex virus—a...
3.0K
Translational Regulation
877
Translational regulation in prokaryotes ensures efficient protein synthesis by controlling ribosome access to mRNA. This regulation is mediated by secondary RNA structures, including translational riboswitches, RNA thermometers, and small RNAs (sRNAs), which respond to intracellular and environmental signals to modulate gene expression.Translational RiboswitchesRiboswitches in the leader region of mRNAs can regulate translation by altering the accessibility of the Shine-Dalgarno (SD) sequence,...
877
The Antiviral System of Bacteria and Archaea: CRISPR
1.1K
CRISPR stands for Clustered Regularly Interspaced Short Palindromic Repeats is a adaptive immune system found in bacteria and archaea that protects against viral infections. This system enables prokaryotic cells to identify, remember, and neutralize foreign genetic elements, primarily bacteriophages, by storing fragments of the invader’s DNA as a genetic memory.The CRISPR immune response begins during an initial infection. Cas (CRISPR-associated) proteins play a central role in this...
1.1K


