Self-assembly of a β-sheet protein governed by relief of electrostatic repulsion relative to van der Waals attraction
Self-assembly of a β-sheet protein governed by relief of electrostatic repulsion relative to van der Waals attraction
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DOI：
10.1021/bm005586w
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发表时间：
2000-12-01
影响因子：
6.2
通讯作者：
Lauffenburger, DA
中科院分区：
文献类型：
--
作者：
Caplan, MR;Moore, PN;Lauffenburger, DA
使用合成的寡肽，N-FKFEFKFEFKFE-C（KFE 12），代表一类肽，可以进行自组装成一个三维的矩阵生物材料，我们表明，自组装发生时，溶液条件降低分子间的电双层排斥低于货车德瓦尔斯吸引力在雅阁与DLVO理论。该理论预测，应该需要平衡离子的临界凝聚浓度以允许组装，并且该浓度应该与升高到六次幂的平衡离子的化合价成反比。我们的实验结果表明，在低pH值下，KFE 12在KCl、K2 SO 4和K3 Fe（CN）（6）三种不同盐溶液中均表现出临界混凝浓度，并且这些临界浓度的相对值遵循预测的阴离子价态依赖性。该理论进一步预测，即使在没有外源盐的情况下，当寡肽呈电中性时，也应该发生自组装。我们的实验结果表明，KFE 12确实形成凝胶时，用NaOH中和。因此，我们对如何控制这类基于寡肽的生物材料的组装获得了基本的理论理解。
Using a synthetic oligopeptide, n-FKFEFKFEFKFE-c (KFE12), representative of a class of peptides that can undergo self-assembly into a three-dimensional matrix biomaterial, we show that the self-assembly occurs when solution conditions reduce intermolecular electrical double-layer repulsion below van der Waals attraction in accord with DLVO theory. This theory predicts that a critical coagulation concentration of counterions should be required to allow assembly and that this concentration should be inversely proportional to the valence of the counterion raised to the sixth power. Our experimental results show that KFE12, at low pH, exhibits critical coagulation concentrations in each of three different salt solutions, KCl, K2SO4, and K3Fe(CN)(6), and that the relative values of these critical concentrations follow the predicted dependence upon anion valence. The theory further predicts that self-assembly should occur when the oligopeptide is electrically neutral even in the absence of exogenous salt. Our experimental results show that KFE12 indeed forms gels when neutralized with NaOH. Thus, we have gained fundamental theoretical understanding of how to control the assembly of this class of oligopeptide-based biomaterials.