The solubility product extends the buffering concept to heterotypic biomolecular condensates.
The solubility product extends the buffering concept to heterotypic biomolecular condensates.
复制标题
DOI：
10.7554/elife.67176
复制
发表时间：
2021-07-08
期刊：
影响因子：
7.7
通讯作者：
Loew LM
中科院分区：
文献类型：
--
作者：
Chattaraj A;Blinov ML;Loew LM
生物分子凝聚体是由多价分子的液-液相分离形成的。来自单一(“同型”)组分的LLP受缓冲控制：在阈值以上，自由单体浓度被钳制，所有添加的分子进入凝聚相。然而，实验和理论都表明，缓冲对于多组分(异型)LLP的浓度依赖性是无效的。使用无网络随机模型，我们证明了LLP可以用溶度积常数(KSP)来描述：自由单体浓度的乘积，解释了由价态控制的理想化学计量比，显示了一个阈值，超过这个阈值，额外的单体被聚集到大的团簇中；这对于同型体系来说简化为简单的缓冲。KSP为各种价态和化学计量比调节稀相的组成。粗粒度空间粒子模拟进一步支持了KSP的作用。因此，溶解度积提供了LLP浓度依赖关系的一般公式。
Biomolecular condensates are formed by liquid-liquid phase separation (LLPS) of multivalent molecules. LLPS from a single ("homotypic") constituent is governed by buffering: above a threshold, free monomer concentration is clamped, with all added molecules entering the condensed phase. However, both experiment and theory demonstrate that buffering fails for the concentration dependence of multicomponent ("heterotypic") LLPS. Using network-free stochastic modeling, we demonstrate that LLPS can be described by the solubility product constant (Ksp): the product of free monomer concentrations, accounting for the ideal stoichiometries governed by the valencies, displays a threshold above which additional monomers are funneled into large clusters; this reduces to simple buffering for homotypic systems. The Ksp regulates the composition of the dilute phase for a wide range of valencies and stoichiometries. The role of Ksp is further supported by coarse-grained spatial particle simulations. Thus, the solubility product offers a general formulation for the concentration dependence of LLPS.