Incorporating Born solvation energy into the three-dimensional Poisson-Nernst-Planck model to study ion selectivity in KcsA K+ channels

doi:10.1103/PhysRevE.96.062416

CORC > 数学与系统科学研究院 > 中国科学院数学与系统科学研究院 > 计算数学与科学工程计算研究所

	Incorporating Born solvation energy into the three-dimensional Poisson-Nernst-Planck model to study ion selectivity in KcsA K+ channels
	Liu, Xuejiao ; Lu, Benzhuo1
刊名	PHYSICAL REVIEW E
	2017-12-26
卷号	96 期号:6 页码:10
ISSN号	2470-0045
DOI	10.1103/PhysRevE.96.062416
英文摘要	Potassium channels are much more permeable to potassium than sodium ions, although potassium ions are larger and both carry the same positive charge. This puzzle cannot be solved based on the traditional Poisson-Nernst-Planck (PNP) theory of electrodiffusion because the PNP model treats all ions as point charges, does not incorporate ion size information, and therefore cannot discriminate potassium from sodium ions. The PNP model can qualitatively capture some macroscopic properties of certain channel systems such as current-voltage characteristics, conductance rectification, and inverse membrane potential. However, the traditional PNP model is a continuum mean-field model and has no or underestimates the discrete ion effects, in particular the ion solvation or self-energy (which can be described by Born model). It is known that the dehydration effect (closely related to ion size) is crucial to selective permeation in potassium channels. Therefore, we incorporated Born solvation energy into the PNP model to account for ion hydration and dehydration effects when passing through inhomogeneous dielectric channel environments. A variational approach was adopted to derive a Born-energy-modified PNP (BPNP) model. The model was applied to study a cylindrical nanopore and a realistic KcsA channel, and three-dimensional finite element simulations were performed. The BPNP model can distinguish different ion species by ion radius and predict selectivity for K+ over Na+ in KcsA channels. Furthermore, ion current rectification in the KcsA channel was observed by both the PNP and BPNP models. The I-V curve of the BPNP model for the KcsA channel indicated an inward rectifier effect for K+ (rectification ratio of similar to 3/2) but indicated an outward rectifier effect for Na+ (rectification ratio of similar to 1/6).
资助项目	National Key Research and Development Program of China[2016YFB0201304] ; Science Challenge Project[TZ2016003] ; China NSF (NSFC)[21573274] ; China NSF (NSFC)[91530102]
WOS研究方向	Physics
语种	英语
出版者	AMER PHYSICAL SOC
WOS记录号	WOS:000418660600018
内容类型	期刊论文
源URL	[http://ir.amss.ac.cn/handle/2S8OKBNM/29284]
专题	计算数学与科学工程计算研究所
通讯作者	Lu, Benzhuo
作者单位	1.Chinese Acad Sci, Natl Ctr Math, State Key Lab Sci & Engn Comp, Beijing 100190, Peoples R China 2.Chinese Acad Sci, Interdisciplinary Sci Acad Math & Syst Sci, Beijing 100190, Peoples R China 3.Univ Chinese Acad Sci, Sch Math Sci, Beijing 100049, Peoples R China
推荐引用方式 GB/T 7714	Liu, Xuejiao,Lu, Benzhuo. Incorporating Born solvation energy into the three-dimensional Poisson-Nernst-Planck model to study ion selectivity in KcsA K+ channels[J]. PHYSICAL REVIEW E,2017,96(6):10.
APA	Liu, Xuejiao,&Lu, Benzhuo.(2017).Incorporating Born solvation energy into the three-dimensional Poisson-Nernst-Planck model to study ion selectivity in KcsA K+ channels.PHYSICAL REVIEW E,96(6),10.
MLA	Liu, Xuejiao,et al."Incorporating Born solvation energy into the three-dimensional Poisson-Nernst-Planck model to study ion selectivity in KcsA K+ channels".PHYSICAL REVIEW E 96.6(2017):10.