相关实验视频
Updated: May 30, 2026

12:27
Measuring Peptide Translocation into Large Unilamellar Vesicles
Published on: January 27, 2012
在平衡条件下,水性的in silico分区和跨膜插入在平衡条件下
Jakob P Ulmschneider1, Jeremy C Smith, Stephen H White
1IWR University of Heidelberg, Germany. jakob@ulmschneider.com
Journal of the American Chemical Society
|August 25, 2011
概括
分子动力学模拟揭示了疏水性如何插入脂质双层. 这项研究澄清了跨膜蛋白质插入的物理和生物疏水性尺度之间的关系.
科学领域:
- 生物物理学的生物物理.
- 分子生物学分子生物学
- 计算化学计算化学
背景情况:
- 新生的跨膜 (TM) 聚被通过转位机制插入脂质双层.
- 生物疏水性尺度与物理尺度相关,但由于实验中的可溶性限制,确切的关系尚不清楚.
研究的目的:
- 为了直接测量水性的插入到脂质双层的自由能量.
- 为了研究分区路径和插入的动力学.
- 为了比较模拟衍生的分区自由能量与跨位元实验数据.
主要方法:
- 微秒分子动力学 (MD) 模拟聚氨酸段的分离进入和退出脂质双层.
- 从平衡状态中直接确定插入的自由能量占用 (表面绑定与跨膜插入).
主要成果:
- 疏水性分成表面结合或跨膜插入的状态;没有观察到水溶性状态.
- 转移自由能量被发现是温度独立的,这表明表面到皮层插入的零过程.
- 模拟的分离自由能量与转位子实验值相关,但显示了偏向较短的转移.
结论:
- MD模拟提供了一种直接的方法来确定膜分离的自由能量,克服实验中的溶解性问题.
- 转位孔介导的分区与自发的面对面层分区相关,但不等同.
- 自由能量转移的温度独立性对理解插入热力学有重大影响.
相关概念视频
Translocation of Proteins into the Mitochondria
Mitochondrial precursors are translocated to the internal subcompartments via independent mechanisms involving distinct protein machineries called translocases.
Sorting of outer membrane proteins:
Mitochondrial outer membrane proteins are of two types: the transmembrane, beta-barrel porins, and the membrane-anchored, alpha-helical proteins. Beta-barrel porin precursors are translocated by the TOM complex and inserted into the outer mitochondrial membrane by the SAM complex. In contrast,...
Sorting of outer membrane proteins:
Mitochondrial outer membrane proteins are of two types: the transmembrane, beta-barrel porins, and the membrane-anchored, alpha-helical proteins. Beta-barrel porin precursors are translocated by the TOM complex and inserted into the outer mitochondrial membrane by the SAM complex. In contrast,...
Protein Transport into the Inner Mitochondrial Membrane
Nuclear encoded mitochondrial precursors are imported to the inner membrane in a multistep process involving two separate translocons, TIM22 and TIM23. TIM23 is a cation-selective pore that remains closed by the N terminal segment of the protein. Negative charges on the TIM23 act as a receptor for the incoming precursor, pulling the positively charged matrix-targeting sequence for peptide insertion and translocation.
Transport of mitochondrial precursors across the TIM23 channel is driven by...
Transport of mitochondrial precursors across the TIM23 channel is driven by...
Insertion of Multi-pass Transmembrane Proteins in the RER
The rough ER membrane synthesizes, assembles, and embeds transmembrane proteins in diverse topologies. These proteins function as transporters or channels and can remain in the ER membrane or are sent to the Golgi complex, lysosome, and cell membrane.
The multipass transmembrane proteins are the type IV integral membrane proteins with multiple topogenic sequences determining their spatial arrangement in the ER membrane. Nearly all multipass proteins lack a cleavable signal sequence and use...
The multipass transmembrane proteins are the type IV integral membrane proteins with multiple topogenic sequences determining their spatial arrangement in the ER membrane. Nearly all multipass proteins lack a cleavable signal sequence and use...
Insertion of Single-pass Transmembrane Proteins in the RER
Integral membrane proteins are proteins adhered to the lipid bilayer of a cell organelle or membrane. They can be of two types: transmembrane integral proteins that span the lipid bilayer and monotopic proteins that are attached to either side of the membrane but do not pass through it.
Integral transmembrane proteins possess transmembrane and extra membrane domains. The transmembrane domains are primarily made of 20-25 hydrophobic amino acids arranged in a helical secondary confirmation. These...
Integral transmembrane proteins possess transmembrane and extra membrane domains. The transmembrane domains are primarily made of 20-25 hydrophobic amino acids arranged in a helical secondary confirmation. These...
Single-pass Transmembrane Proteins
Integral membrane proteins are tightly associated with the cell membrane and play a crucial role in cell communication, signaling, adhesion, and transport of the molecules. Some integral membrane proteins are present only in the membrane monolayer. For example, the enzyme fatty acid amide hydrolase is present in the cytoplasmic side of the membrane monolayer. In contrast, another type of integral membrane protein, also known as a transmembrane protein, spans across the membrane. Transmembrane...
Post-translational Translocation of Proteins to the RER
A sizable fraction of proteins destined for ER are first synthesized in the cell cytosol and then transported across the ER membrane–a process called post-translational translocation. Similar to cotranslationally translocated proteins, these proteins also use the Sec translocon complex to enter the ER lumen.
Targeting proteins to the ER
Hsp40 and Hsp70 chaperone molecules bind the translated proteins in the cytosol to prevent their folding. The chaperone binding helps to keep the signal...
Targeting proteins to the ER
Hsp40 and Hsp70 chaperone molecules bind the translated proteins in the cytosol to prevent their folding. The chaperone binding helps to keep the signal...

