Opposite effects of electrostatics and steric exclusion on bundle formation by F-actin and other filamentous polyelectrolytes
Opposite effects of electrostatics and steric exclusion on bundle formation by F-actin and other filamentous polyelectrolytes
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DOI：
10.1021/bi9711386
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发表时间：
1997-10-14
期刊：
影响因子：
2.9
通讯作者：
Janmey, PA
中科院分区：
文献类型：
--
作者：
Tang, JX;Ito, T;Janmey, PA
一些带正电的多肽和蛋白质束DNA、F-肌动蛋白、微管和病毒，如细丝噬菌体FD和烟草花叶病毒(TMV)，以及由波形蛋白形成的中间细丝，其一般行为是由这些生物聚合物的公共聚电解质性质决定的，这引起带有几个净相反电荷的配体的非特异性结合，吸引人的相互作用解释了随后的横向聚集，区别于这种转变与高浓度下丝状颗粒的液晶形成不同，形态相似的细丝束也可以由不结合大分子细丝的惰性溶质(如聚乙二醇)和蛋白质诱导，但这类束状转变背后的物理化学是截然不同的。特别是，由静电和空间机制引起的成束转变与溶液离子强度和丝状生物聚合物的浓度成反比。在这份报告中阐明的不同机制可能各自有助于在生理条件下形成特定的聚合物束。
A number of positively charged polypeptides and proteins bundle DNA, F-actin, microtubules, and viruses such as filamentous phage fd and tobacco mosaic virus (TMV), as well as intermediate filaments formed by vimentin, The general behavior is dictated by the common polyelectrolyte nature of these biopolymers, which gives rise to nonspecific binding by ligands carrying several net opposite charges, An attractive interaction accounts for the subsequent lateral aggregation, distinguishing this transition from the liquid crystalline formation of filamentous particles at high concentrations, Morphologically similar filament bundles can also be induced by inert solutes such as polyethylene glycol (PEG) and proteins that do not bind the macromolecular filaments, but the physicochemistry underlying this class of bundle transitions is distinct. In particular, bundling transitions induced by electrostatic and steric mechanisms have an opposite dependence on the solution ionic strength and the concentration of the filamentous biopolymers. The distinct mechanisms illustrated in this report may each contribute to the formation of specific polymer bundles under physiological conditions.