核类比诱导的功能的增加纠正了人类DNA聚合酶IOTA容易出错的性质
Amit Ketkar1, Maroof K Zafar, Surajit Banerjee
1Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205-7199, USA.
Journal of the American Chemical Society
|May 29, 2012
概括
人类DNA聚合酶IOTA (hpol ι) 在DNA修复过程中容易出错. 一个修改后的核酸N-MC-dATP稳定了酶的活性部位,通过防止错误配对,提高了酶的准确性.
科学领域:
- 分子生物学分子生物学
- 生物化学 生物化学
- 结构生物学 结构生物学
背景情况:
- Y家族DNA聚合酶对于DNA损伤耐受性至关重要,但可能容易发生错误.
- 人类DNA聚合酶IOTA (hpol ι) 是人类Y家族成员中最容易出错的.
- 了解 hpol ι 的忠实性是 DNA 修复机制的关键.
研究的目的:
- 阐明提高hpol1的保真度的分子基础.
- 调查改性核酸N-MC-dATP在提高hpol ι的准确性方面的作用.
- 为了确定N-MC-dATP如何改变hpol中的基配对偏好.
主要方法:
- 确定了与DNA和核酸复合的hp的三种晶体结构.
- 分析了 hpol ι 的三元复合体,其中包含模板 dT 的 DNA 和传入的 N-MC-dATP.
- 对比了N-MC-dATP,dATP和南MC-dATP的结合和方向.
主要成果:
- N-MC-dATP稳定了腺因环的反方向,模仿了突变性dGTP:dT配对.
- 与未经修改的dATP或南MC-dATP不同,N-MC-dATP没有采用同聚糖基基导向来形成Hoogsteen基对.
- 与胡格斯配对相比,N-MC-dATP的固定反构造导致更有利的基堆和催化效率.
结论:
- N-MC-dATP通过阻止Hoogsteen基配对模式来纠正 hpol ι 的易出错的性质.
- N-MC-dATP的bicyclo[3.1.0]hexane支架施加了增强保真性的构造约束.
- 这项研究揭示了调节人类转化DNA聚合酶的效率和保真性的新策略.
更多相关视频
09:04Studying Ribonucleotide Incorporation: Strand-specific Detection of Ribonucleotides in the Yeast Genome and Measuring Ribonucleotide-induced Mutagenesis
Published on: July 26, 2018
07:38DNA Polymerase Activity Assay Using Near-infrared Fluorescent Labeled DNA Visualized by Acrylamide Gel Electrophoresis
Published on: October 6, 2017
相关概念视频
Proofreading
Synthesis of new DNA molecules is carried out by the enzyme DNA polymerase, which adds nucleotides on the daughter strand complementary to the template DNA strand. DNA polymerase has a higher affinity to add the correct base and ensures fidelity during DNA replication. Furthermore, it exhibits proofreading activity during replication, using an exonuclease domain that cuts off incorrect nucleotides from the nascent DNA strand.
Errors During Replication are Corrected by the DNA Polymerase Enzyme
Errors During Replication are Corrected by the DNA Polymerase Enzyme
Proofreading
Overview
Genome Copying Errors
DNA replication is a well-evolved process that copies millions of base pairs with high fidelity during each cell division. Occasionally a wrong base or a long stretch of wrong bases may get added to the daughter strands. If the errors are left unchecked, cells might accumulate several mutations that might endanger their survival. Therefore, the copying errors are checked and repaired at three levels.
Translesion DNA Polymerases
Translesion (TLS) polymerases rescue stalled DNA polymerases at sites of damaged bases by replacing the replicative polymerase and installing a nucleotide across the damaged site. Doing so, TLS allows additional time for the cell to repair the damage before resuming regular DNA replication.
TLS polymerases are found in all three domains of life - archaea, bacteria, and eukaryotes. Of the different classes of TLS polymerases, members of the Y family are fitted with specialized structures that...
TLS polymerases are found in all three domains of life - archaea, bacteria, and eukaryotes. Of the different classes of TLS polymerases, members of the Y family are fitted with specialized structures that...
Mismatch Repair
Overview
Mismatch Repair
Organisms are capable of detecting and fixing nucleotide mismatches that occur during DNA replication. This sophisticated process requires identifying the new strand and replacing the erroneous bases with correct nucleotides. Mismatch repair is coordinated by many proteins in both prokaryotes and eukaryotes.
The Mutator Protein Family Plays a Key Role in DNA Mismatch Repair
The human genome has more than 3 billion base pairs of DNA per cell. Prior to cell division, that vast amount of genetic...
The Mutator Protein Family Plays a Key Role in DNA Mismatch Repair
The human genome has more than 3 billion base pairs of DNA per cell. Prior to cell division, that vast amount of genetic...
