阴离子大小是否影响核酸离子大气的占用和静电选?
Magdalena Gebala1, Steve Bonilla2, Namita Bisaria1
1Department of Biochemistry, Stanford University , Stanford, California 94305, United States.
Journal of the American Chemical Society
|August 2, 2016
概括
计算模型预测了阴离子大小对核酸离子大气的影响,但实验显示大多数金属离子的最小大小依赖,挑战现有模型并为未来的研究提供信息.
科学领域:
- 生物物理
- 计算生物学
- 生物化学
背景情况:
- 静电相互作用控制着核酸的行为,受周围离子大气的影响.
- 之前的模型表明阴离体大小会影响离子大气占用率,但缺乏实验验证.
研究的目的:
- 在核酸离子大气层上测试阴离子大小影响的计算预测.
- 研究离子大小与核酸折叠中的其他因素的作用.
主要方法:
- 离子计数实验以确定DNA和RNA周围的离子占用.
- 从三维参考交互点 (3D-RISM) 模型中测试盲目的预测.
- 在不同金属离子的存在下监测P4-P6RNA折叠.
主要成果:
- 实验结果与3D-RISM模型的预测相矛盾,即Na(+) 超过了Cs(+).
- 观察到的优先占用,但对其他金属离子没有显著的尺寸依赖偏好.
- RNA折叠的差异归因于阴离子-阴离子相互作用,而不是阴离子大小.
结论:
- 对核酸离子大气层的离子大小影响的现有计算模型需要改进.
- 离子-大气的特性很复杂,离子-离子相互作用在核酸折叠中起着重要作用.
- 这些发现为开发核酸系统的改进计算模型提供了关键数据.
相关概念视频
Factors Affecting Activity Coefficient
1.8K
The extended Debye-Hückel equation indicates that the activity coefficient of an ion in an aqueous solution at 25°C depends on three partially interdependent properties: the ionic strength of the solution, the charge of the ion, and the ion size.
The activity coefficient value for an ion is close to one when the solution has almost zero ionic strength, i.e., when the solution shows close to ideal behavior. As the ionic strength of the solution increases from 0 to 0.1 mol/L, a...
The activity coefficient value for an ion is close to one when the solution has almost zero ionic strength, i.e., when the solution shows close to ideal behavior. As the ionic strength of the solution increases from 0 to 0.1 mol/L, a...
1.8K
Ionic Radii
34.6K
Ionic radius is the measure used to describe the size of an ion. A cation always has fewer electrons and the same number of protons as the parent atom; it is smaller than the atom from which it is derived. For example, the covalent radius of an aluminum atom (1s22s22p63s23p1) is 118 pm, whereas the ionic radius of an Al3+ (1s22s22p6) is 68 pm. As electrons are removed from the outer valence shell, the remaining core electrons occupying smaller shells experience a greater effective nuclear...
34.6K
Atomic Radii and Effective Nuclear Charge
63.2K
The elements in groups of the periodic table exhibit similar chemical behavior. This similarity occurs because the members of a group have the same number and distribution of electrons in their valence shells.
63.2K
Ionic Strength: Effects on Chemical Equilibria
3.0K
The addition of an inert ionic compound increases the solubility of a sparingly soluble salt. For example, adding potassium nitrate to a saturated solution of calcium sulfate significantly enhances the solubility of calcium sulfate. Le Châtelier's principle cannot predict this shift in the equilibrium. Instead, this could be explained in terms of changes in the effective concentration of the ions in solution in the presence of added inert salt.
In this solution, the primary...
In this solution, the primary...
3.0K
Molecular Structure and Acidity
22.2K
An acid can be deprotonated to form a conjugate base or an anion. If the produced anion is more stable, then the acid is stronger. On the contrary, if the anion is unstable, then the acid is weaker. Hence, to determine the acidity of the compound, the stability of its conjugate base is studied using various factors.
The size effect explains the change in atomic size on acidity. When comparing the acids formed from elements that belong to the same column in the periodic table, their atomic sizes...
The size effect explains the change in atomic size on acidity. When comparing the acids formed from elements that belong to the same column in the periodic table, their atomic sizes...
22.2K
Crystal Field Theory - Octahedral Complexes
31.5K
Crystal Field Theory
To explain the observed behavior of transition metal complexes (such as colors), a model involving electrostatic interactions between the electrons from the ligands and the electrons in the unhybridized d orbitals of the central metal atom has been developed. This electrostatic model is crystal field theory (CFT). It helps to understand, interpret, and predict the colors, magnetic behavior, and some structures of coordination compounds of transition metals.
CFT focuses on...
To explain the observed behavior of transition metal complexes (such as colors), a model involving electrostatic interactions between the electrons from the ligands and the electrons in the unhybridized d orbitals of the central metal atom has been developed. This electrostatic model is crystal field theory (CFT). It helps to understand, interpret, and predict the colors, magnetic behavior, and some structures of coordination compounds of transition metals.
CFT focuses on...
31.5K


