来自细菌免疫系统的RNA引导监控复合物的结构
Blake Wiedenheft1,2, Gabriel C Lander3, Kaihong Zhou1,2
1Howard Hughes Medical Institute, University of California, Berkeley, California 94720, USA.
Nature
|September 23, 2011
概括
细菌使用CRISPR-Cas系统通过整合外来DNA来防御病毒. 由CRISPR衍生RNAs (crRNAs) 指导的级联复合体,识别和结合入侵的核酸,启动它们的破坏.
科学领域:
- 微生物学 微生物学
- 分子生物学分子生物学
- 结构生物学 结构生物学
背景情况:
- 细菌和古生物通过DNA整合到CRISPR loci中对病毒和质粒产生抵抗力.
- 克里斯普尔位点记录了外来DNA的接触,并产生克里斯普尔衍生RNAs (crRNAs) 进行防御.
- 在大肠杆菌中,crRNAs是布复合体的一部分,对细菌菌体保护至关重要.
研究的目的:
- 阐明CRISPR介导的抗病毒防御的结构基础.
- 确定布复合体在目标结合之前和之后的亚纳米结构.
主要方法:
- 使用冷电子显微镜可视化布综合体.
- 在Cascade的无约束状态和目标约束状态中进行了结构分析.
主要成果:
- 布综合体呈现出一种海马形状的结构,其crRNA沿着蛋白质子单元显示.
- 该结构揭示了crRNA保护和可用于基配对的可用性.
- 目标结合会诱导布中的构造变化,这可能是Cas3核酶招募的信号.
结论:
- 确定的结构为CRISPR-Cas抗病毒防御的机制提供了洞察力.
- 布的架构促进了crRNA引导的识别和随后的破坏外来核酸.
相关概念视频
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


