相关实验视频
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Nanomanipulation of Single RNA Molecules by Optical Tweezers
Published on: August 20, 2014
一个序列,两个 ribozymes:新的 ribozyme 折叠的出现的含义
1Whitehead Institute for Biomedical Research and Department of Biology, Massachusetts Institute of Technology, 9 Cambridge Center, Cambridge, MA 02142, USA.
概括
一个单一的RNA序列可以折叠成两个不同的 ribozyme 结构,催化不同的反应. 这一发现表明RNA折叠可以在没有中间步骤的情况下从现有的RNA折叠进化,暗示了多种RNA的共同祖先.
科学领域:
- 生物化学 生物化学
- 分子生物学分子生物学
- 进化生物学 进化生物学
背景情况:
- RNA分子可以作为酶,称为 ribozymes.
- 新RNA结构和功能的演变尚未完全理解.
- 现有的模型通常假设顺序发展或基因重复用于功能分歧.
研究的目的:
- 为了研究一个单一的RNA序列是否可以采用多个进化上不同的 ribozyme 折叠.
- 探索RNA结构和功能的快速进化分歧的潜力.
- 挑战RNA进化和基因重复现有的范式.
主要方法:
- 设计和合成一个特定的RNA序列.
- 对RNA的折叠能力的实验性表征.
- 测试不同 ribozyme 结构的催化活性.
- 对序列变异及其进化途径的分析.
主要成果:
- 一个单一的RNA序列被确定,可以折叠成两个无关的 ribozyme 结构.
- 每个折叠都催化了不同的酶反应.
- 微小的序列修改允许通过中性突变进入任何折叠.
- 这两个折叠没有共同的结构元素.
结论:
- 新的RNA折叠可以从现有的RNA折叠中出现,而不需要不活跃的中间体.
- 这种机制为RNA的快速功能和结构分歧提供了一条途径.
- 这表明,没有明显相似性的RNA可能具有共同的进化起源.
- 功能分歧可能会在RNA进化过程中先发生基因重复.
相关概念视频
RNA Structure
Overview
The basic structure of RNA consists of a five-carbon sugar and one of four nitrogenous bases. Although most RNA is single-stranded, it can form complex secondary and tertiary structures. Such structures play essential roles in the regulation of transcription and translation.
Different Types of RNA Have the Same Basic Structure
There are three main types of ribonucleic acid (RNA): messenger RNA (mRNA), transfer RNA (tRNA), and ribosomal RNA (rRNA). All three RNA types consist of a...
The basic structure of RNA consists of a five-carbon sugar and one of four nitrogenous bases. Although most RNA is single-stranded, it can form complex secondary and tertiary structures. Such structures play essential roles in the regulation of transcription and translation.
Different Types of RNA Have the Same Basic Structure
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Bacterial RNA Polymerase
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...
Riboswitches
Riboswitches are non-coding mRNA domains that regulate the transcription and translation of downstream genes without the help of proteins. Riboswitches bind directly to a metabolite and can form unique stem-loop or hairpin structures in response to the amount of the metabolite present. They have two distinct regions – a metabolite-binding aptamer and an expression platform.
The aptamer has high specificity for a particular metabolite which allows riboswitches to specifically regulate...
The aptamer has high specificity for a particular metabolite which allows riboswitches to specifically regulate...
Ribozymes
The term ribozyme is used for RNA that can act as an enzyme. Ribozymes are mainly found in selected viruses, bacteria, plant organelles, and lower eukaryotes. Ribozymes were first discovered in 1982 when Tom Cech’s laboratory observed Group I introns acting as enzymes. This was shortly followed by the discovery of another ribozyme, Ribonulcease P, by Sid Altman’s laboratory. Both Cech and Altman received the Nobel Prize in chemistry in 1989 for their work on ribozymes.
Ribozymes can be...
Ribozymes can be...
Ribosome Profiling
Ribosome profiling or ribo-sequencing is a deep sequencing technique that produces a snapshot of active translation in a cell. It selectively sequences the mRNAs protected by ribosomes to get an insight into a cell’s translation landscape at any given point in time.
Applications of ribosome profiling
Ribosome profiling has many applications, including in vivo monitoring of translation inside a particular organ or tissue type and quantifying new protein synthesis levels.
The technique helps...
Applications of ribosome profiling
Ribosome profiling has many applications, including in vivo monitoring of translation inside a particular organ or tissue type and quantifying new protein synthesis levels.
The technique helps...
Ribozymes
The term ribozyme is used for RNA that can act as an enzyme. Ribozymes are mainly found in selected viruses, bacteria, plant organelles, and lower eukaryotes. Ribozymes were first discovered in 1982 when Tom Cech’s laboratory observed Group I introns acting as enzymes. This was shortly followed by the discovery of another ribozyme, Ribonulcease P, by Sid Altman’s laboratory. Both Cech and Altman received the Nobel Prize in chemistry in 1989 for their work on ribozymes.
Ribozymes can be...
Ribozymes can be...

