時間解像度結晶学は,光によるDNA修復を捉える
Contact us if these videos are not relevant.
Contact us if these videos are not relevant.
PubMedで要約を見る
まとめ
この要約は機械生成です。フォトリアーゼは,興奮したフラビンアデニンジヌクレオチド (FAD) コファクターを捕まえてDNAを修復するために光を使用します. この酵素はDNAへの電子移転を促進し,新しい単一結合中間体と段階的な製品放出によって損傷を修復します.
科学分野
- 生物化学
- 分子生物学
- 構造生物学
背景
- フォトリアーゼはDNA修復に不可欠な酵素で 紫外線によるダメージを逆転させるために 光エネルギーを利用します
- フォトリアーゼの触媒機構を理解することは,DNA修復経路を理解するために不可欠です.
研究 の 目的
- 光解酵素で触媒化されたDNA修復の反応中間物質とメカニズムを解明する.
- 酵素の触媒サイクル中の一時的な状態を捕捉し,特徴づけること.
主な方法
- 短命の中間物質を捕捉するために時間解像度結晶学を使用した.
- 異なる時間点における酵素-共因子-DNA複合体の構造分析
主要な成果
- フォトリアーゼは,フラビンアデニンジヌクレオチド (FAD) の興奮状態を曲げられた形状に閉じ込めます.
- 刺激されたFADから損傷したDNAへの電子の転送が修復プロセスを開始します
- DNA修復には単一結合の中間体があり,段階的にチミン塩基が放出されます.
結論
- この研究は,曲げられたFAD興奮状態と単一結合の中間体を含むDNA修復のための新しいメカニズムを明らかにしています.
- 3'チミンが最初に放出される段階的な産物放出は,活性部位の混雑と破壊された水素結合によって決定される.
関連する概念動画
The basic reaction of homologous recombination (HR) involves two chromatids that contain DNA sequences sharing a significant stretch of identity. One of these sequences uses a strand from another as a template to synthesize DNA in an enzyme-catalyzed reaction. The final product is a novel amalgamation of the two substrates. To ensure an accurate recombination of sequences, HR is restricted to the S and G2 phases of the cell cycle. At these stages, the DNA has been replicated already and the...
The double-stranded structure of DNA has two major advantages. First, it serves as a safe repository of genetic information where one strand serves as the back-up in case the other strand is damaged. Second, the double-helical structure can be wrapped around proteins called histones to form nucleosomes, which can then be tightly wound to form chromosomes. This way, DNA chains up to 2 inches long can be contained within microscopic structures in a cell. A double-stranded break not only damages...
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...
Overview
Exposure to mutagens can damage DNA and result in bulky lesions that distort the double-helix structure or impede proper transcription. Damaged DNA can be detected and repaired in a process called nucleotide excision repair (NER). NER employs a set of specialized proteins that first scan DNA to detect a damaged region. Next, NER proteins separate the strands and excise the damaged area. Finally, they coordinate the replacement with new, matching nucleotides.
DNA distortion and damage
In order to be passed through generations, genomic DNA must be undamaged and error-free. However, every day, DNA in a cell undergoes several thousand to a million damaging events by natural causes and external factors. Ionizing radiation such as UV rays, free radicals produced during cellular respiration, and hydrolytic damage from metabolic reactions can alter the structure of DNA. Damages caused include single-base alteration, base dimerization, chain breaks, and cross-linkage.
Chemically...
During replication, the complementary strands in double-stranded DNA are synthesized at different rates. Replication first begins on the leading strand. Replication starts later, occurs more slowly, and proceeds discontinuously on the lagging strand.
There are several major differences between synthesis of the leading strand and synthesis of the lagging strand. 1) Leading strand synthesis happens in the direction of replication fork opening, whereas lagging strand synthesis happens in the...