本质硬性和Θ-溶剂状态在内在无序的蛋白质中:对液态-液态相分离的影响
Lipika Baidya1, Kurt Kremer2, Govardhan Reddy1
1Solid State and Structural Chemistry Unit, Indian Institute of Science, Bengaluru, Karnataka 560012, India.
PNAS nexus
|February 21, 2025
概括
计算机模拟显示,在内在无序蛋白质 (IDP) 中,液-液相分离的溶剂条件 (Θ-模式) 取决于链的长度. 有限尺寸效应和链条刚度影响性质,需要仔细分析以准确确定 Θ 模式.
科学领域:
- 生物物理学的生物物理.
- 计算生物学 计算生物学
- 聚合物物理 聚合物物理
背景情况:
- 固有无序蛋白质 (IDP) 中的液态相分离 (LLPS) 对细胞组织至关重要.
- 定义好和坏溶剂条件之间的过渡的 Θ 模式对LLPS至关重要.
- 像小角度X射线散射 (SAXS) 和单分子光共振能量转移 (smFRET) 等实验技术在确定有限长度IDP的 Θ 模式时显示出差异.
研究的目的:
- 通过计算机模拟,研究链条长度对IDP的 Θ 模式的影响.
- 为了调和通过SAXS和smFRET获得的 Θ 模式的不同实验观测.
- 了解蛋白质刚度和有限大小影响对溶液中的IDP行为的影响.
主要方法:
- 聚聚胺和聚氨酸 IDP 模型的粗粒度计算机模拟.
- 改变辅溶剂 (尿素和三甲基胺N-氧化物) 的度以调整溶剂质量.
- 对结构因子 (模仿SAXS) 和对距离 (模仿smFRET) 的分析,以确定 Θ 模式.
主要成果:
- 由于固有的刚性,IDP在短长度尺度上表现出扩展的形状,无论溶剂质量如何.
- 对于短的IDP (N ≤ 25),LLPS倾向性不能仅仅从单链属性来预测.
- 对于有限大小的IDP,SAXS和smFRET之间的 Θ-模式确定中的差异仅在大链长度 (N) 上趋同.
- 在 Θ 模式下,旋转半径 (Rg) 遵循特定的缩放关系,使得能够准确地提取 Θ 模式.
结论:
- 有限大小的校正是必不可少的,并且在确定 Θ 模式时根据不同的 IDP 属性而有所不同.
- 链条的刚性和热块大小显著影响了IDP属性的分析和 Θ 模式的识别.
- 对Rg的衍生缩放关系提供了一种可靠的方法,用于准确识别IDP中的 Θ-溶剂体制.
相关概念视频
Bending of Members Made of Several Materials
138
In analyzing a structural member composed of two different materials with identical cross-sectional areas, it is crucial to understand how their distinct elastic properties affect the member's response under load. The analysis involves assessing stress and strain distributions using the transformed section concept, which accounts for variations in material properties.
Hooke's Law determines stress in each material, stating that stress is proportional to strain but varies due to each...
Hooke's Law determines stress in each material, stating that stress is proportional to strain but varies due to each...
138
Hooke's Law
339
Hooke's law, a pivotal principle in material science, establishes that the strain a material undergoes is directly proportional to the applied stress, defined by a factor called the modulus of elasticity or Young's modulus.
339
Relation between Poisson's ratio, Modulus of Elasticity and Modulus of Rigidity
240
Deformation occurs in axial and transverse directions when an axial load is applied to a slender bar. This deformation impacts the cubic element within the bar, transforming it into either a rectangular parallelepiped or a rhombus, contingent on its orientation. This transformation process induces shearing strain. Axial loading elicits both shearing and normal strains. Applying an axial load instigates equal normal and shearing stresses on elements oriented at a 45° angle to the load axis.
240
Flexural Stress
230
When analyzing bending in symmetric members, it's crucial to understand how stresses distribute when subjected to bending moments. This stress distribution is effectively described by applying fundamental mechanics and material science principles, particularly Hooke's Law for elastic materials.
Hooke's Law states that within the material's elastic limits, stress is directly proportional to strain. In a member experiencing a bending moment, the strain at any point is relative to...
Hooke's Law states that within the material's elastic limits, stress is directly proportional to strain. In a member experiencing a bending moment, the strain at any point is relative to...
230
Strain and Elastic Modulus
3.5K
The quantity that describes the deformation of a body under stress is known as strain. Strain is given as a fractional change in either length, volume, or geometry under tensile, volume (also known as bulk), or shear stress, respectively, and is a dimensionless quantity. The strain experienced by a body under tensile or compressive stress is called tensile or compressive strain, respectively. In contrast, the strain experienced under bulk stress and shear stress is known as volume and shear...
3.5K
Elastic Strain Energy for Shearing Stresses
154
As discussed in previous lessons, strain energy in a material is the energy stored when it is elastically deformed, a concept crucial in materials science and mechanical engineering. This energy results from the internal work done against the cohesive forces within the material. When a material undergoes shearing stress and corresponding shearing strain, the strain energy density, which is the energy stored per unit volume, is calculated. Within the elastic limit, where the stress is...
154


