厚度和网格:外膜如何抵抗细胞壁所施加的压力
David Ryoo1, Hyea Hwang2, James C Gumbart3
1Interdisciplinary Bioengineering Graduate Program, Georgia Institute of Technology, Atlanta, Georgia 30332, United States.
The journal of physical chemistry. B
|May 24, 2024
概括
含有外膜 (OM) 和细胞壁 (CW) 的グラム阴性细菌细胞外,在压力下保持结构完整性. OM 显著促进了机械稳定性,即使在CW被拉伸时.
科学领域:
- 微生物学 微生物学
- 生物物理学的生物物理.
- 计算生物学 计算生物学
背景情况:
- 阴性细菌具有复杂的细胞外,包括外膜 (OM),内膜 (IM) 和糖体细胞壁 (CW).
- 这种由布劳恩脂蛋白 (Lpp) 增强的结构,提供了抵御压等环境压力的机械稳定性.
- 虽然研究了单个组件的抗压能力,但OM-CW系统的组合机械性能仍然不太了解.
研究的目的:
- 通过计算来研究格兰氏阴性细菌细胞外的机械稳定性,特别是组合OM-CW系统.
- 量化OM在连接到应力CW时对抗压的贡献.
- 评估蛋白TolC对OM机械性能的影响.
主要方法:
- 构建模拟不同程度CW应变的OM-CW系统的多个计算模型.
- 在模型中包括OM和CW之间的布劳恩脂蛋白 (Lpp) 连接.
- 在模拟应变下分析OM面积变化和系统面积膨胀模块.
- 模拟嵌入OM的TolC蛋白质,以评估其对硬度的影响.
主要成果:
- OM有效地抵御CW的张力,即使CW被拉伸到其宽松面积的2.5倍,也只会减少3至5%的面积.
- OM-CW 系统的面积膨胀模块随着 CW 应变的增加而增加,这表明电阻增加.
- OM对细菌细胞外的整体机械稳定性起着至关重要的作用.
- 将蛋白 TolC 嵌入到 OM 中会增加它的刚性.
结论:
- 格拉姆阴性细菌细胞外由于OM和CW之间的相互作用而表现出显著的机械弹性.
- 在压下,OM在维持细胞外完整性方面发挥着至关重要的作用.
- 蛋白TolC可以增强OM的机械特性,可能有助于细胞防御机制.
更多相关视频
相关概念视频
Plant Cell Wall
3.9K
Plant cells have a cell wall, a rigid outer covering that protects the cell and provides shape and support. During cell division, a mixture of enzymes, proteins, and glucose molecules is transported via vesicles to the center of the cell. These vesicles continuously fuse and build a cell plate between the dividing cells. As the cell plate matures, new polysaccharides are added to it to form the cell walls of the daughter cells. The predominant polysaccharide in the cell wall is cellulose, made...
3.9K
Mechanisms of Membrane-bending
2.7K
The living membranes are flexible due to their fluid mosaic nature; however, their bending into different shapes is an active process regulated by specific lipids and proteins. The membrane bending can be transient as seen in vesicles or stable for a long time as in microvilli. Cells regulate the size, location, and duration of the membrane curvature.
Membrane bending can happen due to intrinsic changes in lipid composition or extrinsic association with different proteins. The proteins involved...
Membrane bending can happen due to intrinsic changes in lipid composition or extrinsic association with different proteins. The proteins involved...
2.7K
Cell-matrix's Response to Mechanical Forces
2.6K
In animal cells, the extracellular matrix allows cells within tissues to withstand external stresses and transmits signals from the outside of the cell to the inside. The extracellular matrix is extensive, and its composition varies between different types of tissues. For example, the reticular fibers and ground substance make up the ECM in loose connective tissue, while collagen and bone minerals make up the ECM of bone tissue.
Anchoring junctions mechanically attach a cell to the...
Anchoring junctions mechanically attach a cell to the...
2.6K
Cell Motility through Blebbing
1.9K
Blebs are a type of membrane protrusion formed by the internal hydrostatic pressure of the cytoplasm. Blebs are observed in several cell types, including fibroblasts, immune cells, and single-celled organisms like the amoeba. The primary function of blebs is cell locomotion and apoptosis, but they are also found during necrosis and cell division. The life cycle of a bleb comprises an initiation phase followed by the expansion and retraction phases.
Blebbing Through the Matrix
In multicellular...
Blebbing Through the Matrix
In multicellular...
1.9K
Tonicity in Plants
53.3K
Tonicity describes the capacity of a cell to lose or gain water. It depends on the quantity of solute that does not penetrate the membrane. Tonicity delimits the magnitude and direction of osmosis and results in three possible scenarios that alter the volume of a cell: hypertonicity, hypotonicity, and isotonicity. Due to differences in structure and physiology, tonicity of plant cells is different from that of animal cells in some scenarios.
53.3K
Tonicity in Animals
3.1K
Tonicity describes the amount of solute in a solution. The measure of the tonicity of a solution, or the total amount of solutes dissolved in a specific amount of solution, is called its osmolarity. Three terms—hypotonic, isotonic, and hypertonic—are used to relate the osmolarity of a cell to the osmolarity of the extracellular fluid that contains the cells. In a hypotonic solution, such as tap water, the extracellular fluid has a lower concentration of solutes than the fluid inside...
3.1K


