Human insulin adsorption kinetics, conformational changes and amyloidal aggregate formation on hydrophobic surfaces
Human insulin adsorption kinetics, conformational changes and amyloidal aggregate formation on hydrophobic surfaces
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DOI：
10.1016/j.actbio.2012.09.025
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发表时间：
2013-02-01
影响因子：
9.7
通讯作者：
Weidenhaupt, Marianne
中科院分区：
文献类型：
--
作者：
Nault, Laurent;Guo, Perry;Weidenhaupt, Marianne
胰岛素淀粉样聚集体在材料表面上的形成是具有重要药学和医学意义的众所周知的现象。利用表面等离子体共振成像，我们监测胰岛素吸附模型疏水表面在真实的时间。胰岛素分两个阶段吸附：首先是非常快的阶段（小于1分钟），其中形成蛋白质单层，接着是可以持续至少1小时的较慢阶段，其中存在多层蛋白质聚集体。解离动力学揭示了两个胰岛素群体的存在，缓慢相互转化：一个快速解离池和一个池的强烈结合的胰岛素聚集体。在蛋白质溶液与表面接触1小时后，吸附的胰岛素实际上已经停止从表面解离。用衰减全反射-傅里叶变换红外光谱法研究了吸附胰岛素的构象。酰胺A和酰胺II'谱带的特征位移与胰岛素吸附有关。酰胺I带也不同于可溶性或聚集的胰岛素，并且其随时间缓慢演变。观察到1708 cm（-1）峰，其表征了胰岛素吸附超过30 min的时间。最后，硫磺素T（淀粉样蛋白纤维中存在的延伸β-折叠结构的标记物）在30-40 min后与吸附的胰岛素结合。总之，这些结果表明，在与疏水表面结合后诱导的胰岛素构象变化允许溶液中的胰岛素进一步结合。因此，吸附的胰岛素是沿着α至β结构转变的中间体，其导致在这些材料表面上形成淀粉样纤维。(C)2012 Acta Materialia Inc.由爱思唯尔有限公司出版。保留所有权利。
The formation of insulin amyloidal aggregates on material surfaces is a well-known phenomenon with important pharmaceutical and medical implications. Using surface plasmon resonance imaging, we monitor insulin adsorption on model hydrophobic surfaces in real time. Insulin adsorbs in two phases: first, a very fast phase (less than 1 min), where a protein monolayer forms, followed by a slower one that can last for at least I h, where multilayered protein aggregates are present. The dissociation kinetics reveals the presence of two insulin populations that slowly interconvert: a rapidly dissociating pool and a pool of strongly bound insulin aggregates. After I h of contact between the protein solution and the surface, the adsorbed insulin has practically stopped dissociating from the surface. The conformation of adsorbed insulin is probed by attenuated total reflection-Fourier transform infrared spectroscopy. Characteristic shifts in the amide A and amide II' bands are associated with insulin adsorption. The amide I band is also distinct from that of soluble or aggregated insulin, and it slowly evolves in time. A 1708 cm(-1) peak is observed, which characterizes insulin adsorbed for times longer than 30 min. Finally, Thioflavin T, a marker of extended beta-sheet structures present in amyloid fibers, binds to adsorbed insulin after 30-40 min. Altogether, these results reveal that the conformational change induced in insulin upon binding to hydrophobic surfaces allows further insulin binding from the solution. Adsorbed insulin is thus an intermediate along the alpha-to-beta structural transition that results in the formation of amyloidal fibers on these material surfaces. (C) 2012 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.