DNA-PKcs的晶体结构揭示了一个由HEAT重复组成的大型开放环摇篮
Bancinyane L Sibanda1, Dimitri Y Chirgadze, Tom L Blundell
1Department of Biochemistry, University of Cambridge, Old Addenbrooke's site, 80 Tennis Court Road, Cambridge CB2 1GA, UK. lynn@cryst.bioc.cam.ac.uk
Nature
|December 22, 2009
概括
确定了人类DNA依赖蛋白激酶催化子单元 (DNA-PKcs) 的晶体结构,揭示了它在DNA双链断裂修复中的作用. 这一发现提供了对基因组稳定性和癌症预防机制的见解.
科学领域:
- 分子生物学分子生物学
- 结构生物学 结构生物学
- 生物化学 生物化学
背景情况:
- DNA双链断裂 (DSB) 是来自内源和外源的关键DNA病变.
- 未修复或错误修复的DSB可以导致基因组不稳定,细胞死亡或癌症.
- 含有DNA-PKcs和Ku70/Ku80的全酶DNA依赖蛋白激酶 (DNA-PK) 是用于DSB修复的非同类末端结合 (NHEJ) 的核心.
研究的目的:
- 阐明DNA双链断裂修复中的DNA-PKcs功能的结构基础.
- 提供人类DNA-PKcs的第一个晶体结构,详细说明其整体折叠和域组织.
主要方法:
- 使用X射线晶体学来确定人类DNA-PKcs.的结构.
- 进行了高分辨率 (6.6 Å) 结构分析,以可视化蛋白质的折叠.
主要成果:
- 人类DNA-PKcs的晶体结构揭示了一个独特的折叠,其特点是众多的alpha-helical HEAT重复.
- 这些HEAT重复方便聚链曲成一个空洞的圆形结构.
- 碳氧终端激酶域位于该结构的顶部,内部位于DNA结合的HEAT重复域.
结论:
- 确定DNA-PKcs的结构呈现出一种灵活的摇篮状构造,这对于促进DNA双链断裂修复至关重要.
- 了解DNA-PKcs的结构为NHEJ途径和DNA损伤反应提供了机理性的见解.
- 这些结构信息可以为在癌症治疗中准DNA修复途径的策略提供信息.
相关概念视频
PCR
193.0K
Overview
193.0K
DNA Helicases
19.4K
DNA unwinding helicase enzymes are a type of motor protein. Motor proteins can translocate along filaments or polymers using energy generated from ATP hydrolysis. Helicases are involved in all the important cellular processes where DNA unwinding is required, such as DNA replication, repair, recombination, and transcription. They are present in all living organisms, but vary in their structure, function, and mechanism of action. For example, in prokaryotes, DnaB helicase binds and translocates...
19.4K
DNA Topoisomerases
32.3K
Topoisomerases are enzymes that relax overwound DNA molecules during various cell processes, including DNA replication and transcription. These enzymes regulate positive and negative DNA supercoiling without changing the nucleotide sequence. DNA overwinding in a clockwise direction results in positively supercoiled DNA, whereas underwinding in a counterclockwise direction produces negatively supercoiled DNA.
Types and Mechanism of action
Topoisomerases are divided into two main types. ...
Types and Mechanism of action
Topoisomerases are divided into two main types. ...
32.3K
Restarting Stalled Replication Forks
5.1K
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,...
5.1K
Single-Strand DNA Binding Proteins
12.9K
For successful DNA replication, the unwinding of double-stranded DNA must be accompanied by stabilization and protection of the separated single strands of the DNA. This crucial task is performed by single-strand DNA-binding (SSB) proteins. They bind to the DNA in a sequence-independent manner, which means that the nitrogenous bases of the DNA need not be present in a specific order for binding of SSB proteins to it. The binding of SSB proteins straightens single-stranded DNA (ssDNA) and makes...
12.9K
Nucleic Acid Structure
8.1K
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...
DNA Structure
DNA...
8.1K


