概括
研究人员在细菌体434抑制剂和cro蛋白中发现了DNA识别螺旋体. 一种混合蛋白表明,这些螺旋体的交换改变了DNA结合特异性,证实了它们的作用.
科学领域:
- 分子生物学分子生物学
- 遗传学 是一个遗传学.
- 蛋白质-DNA相互作用
背景情况:
- 许多DNA结合蛋白利用α螺旋体进行特定的DNA序列识别.
- 菌体434的抑制剂和cro蛋白在结构上是相关的,但具有不同的DNA结合特性.
- 这些蛋白与菌体434运营者 (OR) 内的多个部位相互作用.
研究的目的:
- 通过使用氨基酸序列同类学来识别菌体434抑制剂和克罗蛋白中的假定DNA识别α螺旋体.
- 调查这些假设螺旋在确定DNA结合特异性的作用.
- 设计一种混合蛋白来测试已识别的螺旋的功能.
主要方法:
- 氨基酸序列同质分析用于预测DNA识别螺旋.
- 化学探测 (二甲基硫酸盐) 来绘制蛋白质-DNA接触的地图.
- 蛋白质工程通过交换假定识别螺旋来创建混合抑制器*.
主要成果:
- 该研究在434种抑制蛋白和克罗蛋白中确定了假定的DNA识别α螺旋体.
- 硫酸二甲基的探测揭示了在操作站点上的抑制剂和克罗蛋白的独特DNA结合接触.
- 工程混合蛋白,抑制剂*,表现出克罗蛋白特征的DNA结合接触,而不是原始抑制剂.
结论:
- 已识别的α螺旋对于确定细菌434抑制剂和cro蛋白所产生的特定DNA序列接触至关重要.
- 这些螺旋体的交换有效地将DNA结合特异性从一种蛋白质转移到另一种蛋白质.
- 这项研究直接证实了特定的α螺旋体在这些病毒蛋白的序列选择性DNA识别中的作用.
相关概念视频
02:36RNA Polymerase II Accessory Proteins
Proteins that regulate transcription can do so either via direct contact with RNA Polymerase or through indirect interactions facilitated by adaptors, mediators, histone-modifying proteins, and nucleosome remodelers. Direct interactions to activate transcription is seen in bacteria as well as in some eukaryotic genes. In these cases, upstream activation sequences are adjacent to the promoters, and the activator proteins interact directly with the transcriptional machinery. For example, in...
02:13Cooperative Binding of Transcription Regulators
Transcriptional regulators bind to specific cis-regulatory sequences in the DNA to regulate gene transcription. These cis-regulatory sequences are very short, usually less than ten nucleotide pairs in length. The short length means that there is a high probability of the exact same sequence randomly occurring throughout the genome. Since regulators can also bind to groups of similar sequences, this further increases the chances of random binding. Transcriptional regulators form dimers that...
01:58Prokaryotic Transcriptional Activators and Repressors
The organization of prokaryotic genes in their genome is notably different from that of eukaryotes. Prokaryotic genes are organized, such that the genes for proteins involved in the same biochemical process or function are located together in groups. This group of genes, along with their regulatory elements, are collectively known as an operon. The functional genes in an operon are transcribed together to give a single strand of mRNA known as polycistronic mRNA.
Transcription of prokaryotic...
Transcription of prokaryotic...
02:04Co-activators and Co-repressors
Gene transcription is regulated by the synergistic action of several proteins that form a complex at a gene regulatory site. This is observed in eukaryotes, where the regulation of gene expression is a complex process. Regulatory proteins in eukaryotes can broadly be classified into two types – regulators that bind directly to specific DNA sequences and co-regulators that associate with regulatory proteins but cannot directly bind to the DNA. These co-regulators are further divided into...
01:58Prokaryotic Transcriptional Activators and Repressors
The organization of prokaryotic genes in their genome is notably different from that of eukaryotes. Prokaryotic genes are organized, such that the genes for proteins involved in the same biochemical process or function are located together in groups. This group of genes, along with their regulatory elements, are collectively known as an operon. The functional genes in an operon are transcribed together to give a single strand of mRNA known as polycistronic mRNA.
Transcription of prokaryotic...
Transcription of prokaryotic...
02:04Co-activators and Co-repressors
Gene transcription is regulated by the synergistic action of several proteins that form a complex at a gene regulatory site. This is observed in eukaryotes, where the regulation of gene expression is a complex process. Regulatory proteins in eukaryotes can broadly be classified into two types – regulators that bind directly to specific DNA sequences and co-regulators that associate with regulatory proteins but cannot directly bind to the DNA. These co-regulators are further divided into...