禽流感聚合酶PA(N) 的晶体结构揭示了一个内核酶活性位点
Puwei Yuan1, Mark Bartlam, Zhiyong Lou
1National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China.
Nature
|February 6, 2009
概括
流感病毒PA蛋白 (PA(N)) 的N端域具有内核酶活性,对病毒复制至关重要. 这一发现确定了PA(N) 作为开发新抗流感药物的关键目标.
科学领域:
- 病毒学 病毒学
- 结构生物学 结构生物学
- 生物化学 生物化学
背景情况:
- 异构三体流感病毒聚合酶复合体 (PA,PB1,PB2) 对于病毒RNA复制和转录至关重要.
- 以前认为PB1亚单元具有内核酶活性,而PB2则结合盖结构.
- 帕蛋白的N端区域 (PA(N)) 已涉及到各种功能,包括内核酶活性.
研究的目的:
- 确定来自禽流感H5N1病毒的PA蛋白 (PA(N)) 的N端域的晶体结构.
- 研究PA(N) 的内核酶活性及其在流感病毒聚合酶功能中的作用.
- 评估PA(N) 作为抗流感治疗药物的潜在目标.
主要方法:
- 进行X射线晶体学以确定PA的2.2 Å结构.
- 生物信息分析和与已知的内核酶基因进行比较.
- 位点定向突变发生,以分析已识别的动机.
- 在体内核糖蛋白复制试验.
- 在体外内核核酶测定.
主要成果:
- 的晶体结构揭示了与离子结合的α/β结构.
- 在PA{N}中发现了一种类似于 (P) DX{N}{D/E}XK内核酶特征的基因.
- 突变和功能测定证实了PA(N),而不是PB1,存在对流感聚合酶活性至关重要的内核酶活性位点.
- 在PA(N) 中的内核酶活性位点在流感菌株中高度保留.
结论:
- 帕蛋白 (PA(N)) 的N端域含有对流感病毒复制至关重要的内核酶活性位.
- PA (N) 在流感病毒聚合酶的内核酶活性中发挥着关键作用.
- 该PA(N) 内核酶活性位点的保存性使其成为新型抗流感药物开发的有希望的目标.
相关概念视频
Restarting Stalled Replication Forks
DNA replication is initiated at sites containing predefined DNA sequences known as origins of replication. DNA is unwound at these sites by the minichromosome maintenance (MCM) helicase and other factors such as Cdc45 and the associated GINS complex.The unwound single strands are protected by replication protein A (RPA) until DNA polymerase starts synthesizing DNA at the 5’ end of the strand in the same direction as the replication fork. To prevent the replication fork from falling apart, a...
Eukaryotic RNA Polymerases
RNA Polymerase (RNAP) is conserved in all animals, with bacterial, archaeal, and eukaryotic RNAPs sharing significant sequence, structural, and functional similarities. Among the three eukaryotic RNAPs, RNA Polymerase II is most similar to bacterial RNAP in terms of both structural organization and folding topologies of the enzyme subunits. However, these similarities are not reflected in their mechanism of action.
All three eukaryotic RNAPs require specific transcription factors, of which the...
All three eukaryotic RNAPs require specific transcription factors, of which the...
Leaky Scanning
During most eukaryotic translation processes, the small 40S ribosome subunit scans an mRNA from its 5' end until it encounters the first start AUG codon. The large 60S ribosomal subunit then joins the smaller one to initiate protein synthesis. The location of the translation initiation is largely determined by the nucleotides near the start codon as there may be multiple translation initiation sites present on the mRNA. Marilyn Kozak discovered that the sequence RCCAUGG (where R stands for...
Nucleic Acid Structure
The pentose sugar in DNA is deoxyribose, while in RNA the pentose sugar is ribose. The difference between the sugars is the presence of the hydroxyl group on the ribose's second carbon and a hydrogen on the deoxyribose's second carbon. The phosphate residue attaches to the hydroxyl group of the 5′ carbon of one sugar and the hydroxyl group of the 3′ carbon of the sugar of the next nucleotide, which forms a 5′ to 3′ phosphodiester linkage.
DNA Structure
DNA has a double-helix structure. The...
DNA Structure
DNA has a double-helix structure. The...
The Antiviral System of Bacteria and Archaea: CRISPR
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 defense.
Influenza
Influenza is an acute, highly communicable viral disease that affects the respiratory tract and is responsible for seasonal epidemics worldwide. Influenza A is the most prevalent type associated with widespread outbreaks and is subtyped based on two surface glycoproteins: hemagglutinin (H) and neuraminidase (N), as in H1N1. These glycoproteins are essential for viral infectivity, transmission, and immune recognition. Transmission occurs primarily through respiratory droplets and contaminated...


