期刊
JOURNAL OF PHYSICAL CHEMISTRY B
卷 120, 期 33, 页码 8696-8706出版社
AMER CHEMICAL SOC
DOI: 10.1021/acs.jpcb.6b03887
关键词
-
资金
- National Science Foundation [ACI-1053575]
Cytosolic crowding can influence the thermodynamics and kinetics of in vivo chemical reactions. Most significantly, proteins and nucleic acid crowders reduce the accessible volume fraction, phi, available to a diffusing substrate, thereby reducing its effective diffusion rate, D-eff, relative to its rate in bulk solution. However, Deff can be further hindered or even enhanced, when long-range crowder/diffuser interactions are significant. To probe these effects, we numerically estimated D-eff values for small, charged molecules in representative, cytosolic protein lattices up to 0.1 x 0.1 x 0.1 mu m(3) in volume via the homogenized Smoluchowski electro-diffusion equation. We further validated our predictions against D-eff estimates from phi-dependent analytical relationships, such as the Maxwell-Garnett (MG) bound, as well as explicit solutions of the time-dependent electro-diffusion equation. We find that in typical, moderately crowded cell cytoplasm (phi approximate to 0.8), D-eff is primarily determined by phi ; in other words, diverse protein shapes and heterogeneous distributions only modestly impact D-eff. However, electrostatic interactions between diffusers and crowders, particularly at low electrolyte ionic strengths, can substantially modulate D-eff. These findings help delineate the extent that cytoplasmic crowders influence small molecule diffusion, which ultimately may shape the efficiency and timing of intracellular signaling pathways. More generally, the quantitative agreement between computationally expensive solutions of the time-dependent electro-diffusion equation and its comparatively cheaper homogenized form suggest that the latter is a broadly effective model for diffusion in wide-ranging, crowded biological media.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据