对于I组内的催化域中的三基基因基因和基因证据
F Michel1, A D Ellington, S Couture
1Department of Molecular Biology, Massachusetts General Hospital, Boston 02114.
Nature
|October 11, 1990
概括
组I内核,一种 ribozyme,利用新的基础三重相互作用的结构. 这些遗传学共变,超出标准的基配对,对于 ribozyme 功能至关重要.
科学领域:
- 分子生物学分子生物学
- 生物化学 生物化学
- 结构RNA结构RNA结构
背景情况:
- ribozymes 催化化学反应,需要深入了解它们的结构.
- 通过序列比较,化学保护和遗传研究,I组内的二次结构得到了很好的确立.
- 遗传学数据在预测三级RNA相互作用方面已被证明是有效的,如转移RNA和核糖体RNA所示.
研究的目的:
- 为了识别超出正规基配对的I组内中的新型三级相互作用.
- 研究RNA序列中的进化共变,这些共变表明非正规的基因相互作用.
- 通过遗传实验来证实这些预测的相互作用的功能重要性.
主要方法:
- 对I组内的对齐核心区域进行比较序列分析.
- 寻找未由沃森-克里克或摇摆基配对解释的基系共变.
- 使用基因实验 (补偿突变) 在Tetrahymena和sunY内部.
主要成果:
- 在I组内子中确定了两种类型遗传共变的实例.
- 这些协同变异最好通过存在与结合的三基的存在来解释,类似于转移RNA中的三基.
- 遗传实验证实了这些基三重相互作用对 ribozyme 结构的重要性.
结论:
- 为了结构稳定性,除了沃森-克里克和摇摆对外,I组内还采用了三基相互作用.
- 这些非正规的相互作用在进化上是保存的,并且在功能上对 ribozyme 活性很重要.
- 这些发现扩大了我们对RNA结构动机及其在催化中的作用的理解.
相关概念视频
Phylogenetic Trees
Phylogenetic trees come in many forms. It matters in which sequence the organisms are arranged from the bottom to the top of the tree, but the branches can rotate at their nodes without altering the information. The lines connecting individual nodes can be straight, angled, or even curved.The length of the branches can depict time or the relative amount of change among organisms. For instance, the branch length might indicate the number of amino acid changes in the sequence that underlies the...
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...
Evolutionary Relationships through Genome Comparisons
Genome comparison is one of the excellent ways to interpret the evolutionary relationships between organisms. The basic principle of genome comparison is that if two species share a common feature, it is likely encoded by the DNA sequence conserved between both species. The advent of genome sequencing technologies in the late 20th century enabled scientists to understand the concept of conservation of domains between species and helped them to deduce evolutionary relationships across diverse...
Gene Duplication and Divergence
The seminal work of Ohno in 1970 popularized the idea of gene duplication and divergence. DNA sequence comparison studies reveal that a large portion of the genes in bacteria, archaebacteria, and eukaryotes was generated by gene duplication and divergence, indicating its critical role in evolution.
The duplicated copies of the gene are called Paralogs. Paralogs with similar sequences and functions form a gene family. Across several species, a large number of gene families are characterized.
The duplicated copies of the gene are called Paralogs. Paralogs with similar sequences and functions form a gene family. Across several species, a large number of gene families are characterized.
Exon Recombination
The evolution of new genes is critical for speciation. Exon recombination, also known as exon shuffling or domain shuffling, is an important means of new gene formation. It is observed across vertebrates, invertebrates, and in some plants such as potatoes and sunflowers. During exon recombination, exons from the same or different genes recombine and produce new exon-intron combinations, which might evolve into new genes.
Exon shuffling follows “splice frame rules.” Each exon has three reading...
Exon shuffling follows “splice frame rules.” Each exon has three reading...
Bacterial Transcription
RNA polymerase (RNAP) carries out DNA-dependent RNA synthesis in both bacteria and eukaryotes. Bacteria do not have a membrane-bound nucleus. So, transcription and translation occur simultaneously, on the same DNA template.
Transcription can be divided into three main stages, each involving distinct DNA sequences to guide the polymerase. These are:
Transcription can be divided into three main stages, each involving distinct DNA sequences to guide the polymerase. These are:


