Transmembrane ion transport by polyphosphate/poly-(R)-3-hydroxybutyrate complexes.
Transmembrane ion transport by polyphosphate/poly-(R)-3-hydroxybutyrate complexes.
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通过多磷酸盐/聚-(R)-3-羟基丁酸盐复合物进行跨膜离子传输。
DOI：
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发表时间：
2000
期刊：
影响因子：
--
通讯作者：
R. Reusch
中科院分区：
文献类型：
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作者：
R. Reusch
跨膜离子转运是为细胞功能提供能量的关键过程，是由能够区分非常相似的离子并对膜电位变化做出响应的成孔大分子来执行的。人们普遍认为离子通道完全是蛋白质，在细胞进化中相对较晚出现。在这里，我们讨论了两种简单均聚物复合物的离子选择性电压激活通道的形成，即分别源自磷酸盐和乙酸盐的无机多磷酸盐（polyPs）和聚-（R）-3-羟基丁酸盐（PHBs）。每一种都具有独特的分子特征，有利于离子选择、溶剂化和传输。从细菌质膜分离或由合成聚合物制备的两种聚合物的复合物，在平面脂质双层中形成电压依赖性Ca2+选择性通道，该通道对二价阳离子比单价阳离子具有选择性，可渗透Ca2+、Sr2+和Ba2+，并以浓度依赖性方式被过渡金属阳离子阻断。最近，人们发现polyP和PHB都是离子传导蛋白的组成部分：即人红细胞Ca2+-ATP酶泵和浅青紫链霉菌钾通道。 PolyP 和 PHB 对这些蛋白质中离子选择和/或运输的贡献尚不清楚，但它们的存在引起了这样的假设：这些和其他离子转运蛋白是超分子结构，其中蛋白质、polyP 和 PHB 合作形成良好调节的特定阳离子转移系统。
Transmembrane ion transport, a critical process in providing energy for cell functions, is carried out by pore-forming macromolecules capable of discriminating among very similar ions and responding to changes in membrane potential. It is widely regarded that ion channels are exclusively proteins, relatively late arrivals in cell evolution. Here we discuss the formation of ion-selective, voltage-activated channels by complexes of two simple homopolymers, namely, inorganic polyphosphates (polyPs) and poly-(R)-3-hydroxybutyrates (PHBs), derived from phosphate and acetate, respectively. Each has unique molecular characteristics that facilitate ion selection, solvation, and transport. Complexes of the two polymers, isolated from bacterial plasma membranes or prepared from the synthetic polymers, form voltage-dependent, Ca2+-selective channels in planar lipid bilayers that are selective for divalent over monovalent cations, permeant to Ca2+, Sr2+, and Ba2+, and blocked by transition metal cations in a concentration-dependent manner. Recently, both polyP and PHB have been found to be components of ion-conducting proteins: namely, the human erythrocyte Ca2+-ATPase pump and the Streptomyces lividans potassium channel. The contribution of polyP and PHB to ion selection and/or transport in these proteins is yet unknown, but their presence gives rise to the hypothesis that these and other ion transporters are supramolecular structures in which proteins, polyP, and PHB cooperate in forming well-regulated and specific cation transfer systems.
聚-β-羟基丁酸酯在细胞内掺入大肠杆菌和维氏固氮菌的质膜中，改变了天然膜结构。
影响因子：
2.8
作者：
Reusch,R;Hiske,T;Sadoff,H;Harris,R;Beveridge,T
通讯作者：
Beveridge,T