这里的E.E. coli DnaX塞加载器急剧曲DNA,以在口和小间隙上加载β
bioRxiv : the preprint server for biology
|February 6, 2026
概括
细菌DNA片装载器使用独特的DNA曲机制在隙和空隙上装载片,与真核生物片装载器不同. 这一策略对于DNA修复过程至关重要.
科学领域:
- 分子生物学分子生物学
- 生物化学 生物化学
- 遗传学 是一个遗传学.
背景情况:
- 在所有生命形式中,DNA滑动是DNA复制和修复的重要组成部分.
- 紧固件加载器依赖ATP,通过识别入的3'DNA末端,便于紧固件加载.
- 在DNA修复中常见的和小单链DNA (ssDNA) 缺口上的加载器的精确机制尚未完全理解.
研究的目的:
- 为了阐明细菌 * Escherichia coli * DnaX 加载器在隙和小 ssDNA 间隙中的机制.
- 为了比较细菌塞加载机制与其真核生物对应物.
主要方法:
- 使用冷电子显微镜 (cryo-EM) 确定了DnaX加载器和β复合物的结构.
- 进行了体外生化测试,以分析DNA结合和加载活动.
主要成果:
- 细菌DnaX加载器不会解开DNA或稳定地结合5'-dsDNA,与真核生物RFC不同.
- 大肠杆菌β具有一个外部DNA结合部位,可诱导显著的DNA曲 (∼150°).
- 这种DNA曲有助于将3'-dsDNA末端插入β,从而在隙和小间隙处有效地加载.
结论:
- 细菌DnaX塞加载器使用一种独特的DNA曲机制,在隙和小间隙上加载β.
- 这种机制从根本上不同于真核生物RFC所采用的DNA解策略.
- 紧在DNA间隙上的有效加载凸显了它们在DNA修复途径中的重要性.
相关概念视频
Patch Clamp
6.6K
Many fundamental cell functions such as muscle contraction and nerve transmission rely on the electrical signals produced by the movement of positively and negatively charged ions across the cell membrane. One competent method to record current flowing across the whole cell or single ion channel is the patch-clamp technique.
In this method, a glass micropipette containing electrolyte solution is tightly sealed against a small portion of the cell membrane. As a result, a patch of the cell...
In this method, a glass micropipette containing electrolyte solution is tightly sealed against a small portion of the cell membrane. As a result, a patch of the cell...
6.6K
Translesion DNA Polymerases
11.2K
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...
11.2K
Gap Junctions
57.2K
Multicellular organisms employ a variety of ways for cells to communicate with each other. Gap junctions are specialized proteins that form pores between neighboring cells in animals, connecting the cytoplasm between the two, and allowing for the exchange of molecules and ions. They are found in a wide range of invertebrate and vertebrate species, mediate numerous functions including cell differentiation and development, and are associated with numerous human diseases, including cardiac and...
57.2K
Gap Junctions
9.6K
The cytoplasm of adjacent animal cells can exchange small molecules, ions, and secondary messengers via the communication channels which form the gap junctions. These junctions comprise a few hundred to thousands of molecular channels, each made of two halves, called the connexon hemichannel. A connexon is a hexamer of six transmembrane connexin proteins, which assemble radially, thus forming a pore or channel in the center. One connexon hemichannel docks with a corresponding connexon on the...
9.6K
Bending
914
Pure bending is a fundamental concept in structural mechanics, essential for understanding how materials deform under symmetrical loads without direct forces. Pure bending occurs when prismatic members, such as beams, are subjected to equal and opposite moments that induce bending. The phenomenon is crucial as it allows for predicting stress distributions without the influence of axial or shear forces.
In pure bending, the bending stress in a beam is calculated based on the bending moment and...
In pure bending, the bending stress in a beam is calculated based on the bending moment and...
914
Symmetric Member in Bending
605
In the study of the mechanics of materials, analyzing the behavior of prismatic members under opposing couples is crucial for understanding internal stress distributions, which are essential for structural design. When subjected to couples, a prismatic member experiences internal forces that maintain equilibrium. A couple, characterized by two equal and opposite forces, creates a moment but no resultant force. The internal forces at any section cut of the member must balance these external...
605


