Interactions between a luminescent conjugated polyelectrolyte and amyloid fibrils investigated with flow linear dichroism spectroscopy.
Interactions between a luminescent conjugated polyelectrolyte and amyloid fibrils investigated with flow linear dichroism spectroscopy.
复制标题
用流动线性二色性光谱研究发光共轭聚电解质和淀粉样原纤维之间的相互作用。
DOI：
10.1016/j.bbrc.2011.03.132
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发表时间：
2011
影响因子：
3.1
通讯作者：
F. Westerlund
中科院分区：
文献类型：
--
作者：
Jens A. Wigenius;M. Andersson;E. K. Esbjörner;F. Westerlund
发光共轭聚电解质（LCP）已成为一种新的染色剂，用于检测和区分各种淀粉样物质，包括前原纤维聚集体和成熟原纤维沉积物，无论是在体外还是在组织学组织样品中，都比传统的淀粉样蛋白染色剂具有优势。在这里，我们使用线性二色性（LD）光谱剪切对齐下的LCP聚（3-噻吩乙酸）（PTAA）和淀粉样纤维之间的相互作用的特点。淀粉样蛋白结合的PTAA的LD光谱中的阳性特征表明其结合在淀粉样蛋白原纤维核心中的相邻蛋白质侧链之间的凹槽中，平行于原纤维轴，类似于硫磺素-T和刚果红。此外，使用LD，我们记录了与游离染料分离的淀粉样蛋白结合的PTAA的吸收光谱，与溶液中相比显示出约30 nm的红移。这对PTAA作为淀粉样蛋白探针在体外原位的应用具有重要意义，我们演示了如何使用PTAA获得最佳的淀粉样蛋白特异性荧光读数。我们使用最大吸收的变化来估计给定浓度下结合PTAA的分数。当以36倍过量添加时，PTAA结合达到饱和，并且在该浓度下，原纤维中的PTAA密度为每个胰岛素单体4 - 5个单体单元。最后，我们证明，LD强度的变化可以与淀粉样蛋白原纤维的持久性长度的改变，导致在溶液条件的变化，表明这种技术是有用的，以评估这些生物聚合物的宏观性能。
Luminescent conjugated polyelectrolytes (LCPs) have emerged as novel stains to detect and distinguish between various amyloidogenic species, including prefibrillar aggregates and mature fibril deposits, bothin vitroand in histological tissue samples, offering advantages over traditional amyloid stains. We here use linear dichroism (LD) spectroscopy under shear alignment to characterize interactions between the LCP poly(3-thiophene acetic acid) (PTAA) and amyloid fibrils. The positive signature in the LD spectrum of amyloid-bound PTAA suggests that it binds in the grooves between adjacent protein side-chains in the amyloid fibril core, parallel to the fibril axis, similar to thioflavin-T and congo red. Moreover, using LD we record the absorption spectrum of amyloid-bound PTAA in isolation from free dye showing a red-shift by ca 30 nm compared to in solution. This has important implications for the use of PTAA as an amyloid probein situandin vitroand we demonstrate how to obtain optimal amyloid-specific fluorescence read-outs using PTAA. We use the shift in maximum absorption to estimate the fraction of bound PTAA at a given concentration. PTAA binding reaches saturation when added in 36 times excess and at this concentration the PTAA density is 4–5 monomer units per insulin monomer in the fibril. Finally, we demonstrate that changes in LD intensity can be related to alterations in persistence length of amyloid fibrils resulting from changes in solution conditions, showing that this technique is useful to assess macroscopic properties of these biopolymers.