Department of Nuclear and Medical Physics, V.N. Karazin Kharkiv National University, 4 Svobody Sq, Kharkiv, 61022, Ukraine.
J Fluoresc. 2013 Nov;23(6):1229-37. doi: 10.1007/s10895-013-1254-2. Epub 2013 Jun 28.
The last decade has seen unprecedented upsurge of interest in the structural and toxic properties of particular type of protein aggregates, amyloid fibrils, associated with a number of pathological states. In the present study fluorescence spectroscopy technique has been employed to gain further insight into the membrane-related mechanisms of amyloid toxicity. To this end, erythrocyte model system composed of liposomes and hemoglobin was subjected to the action of oligomeric and fibrillar lysozyme. Acrylamide quenching of lysozyme fluorescence showed that solvent accessibility of Trp62 and Trp108 increases upon the protein fibrillization. Resonance energy transfer measurements suggested the possibility of direct complexation between hemoglobin and aggregated lysozyme. Using the novel squaraine dye SQ-1 it was demonstrated that aggregated lysozyme is capable of inhibiting lipid peroxidation processes. Fluorescent probes pyrene, Prodan and diphenylhexatriene were employed to characterize the membrane-modifying properties of hemoglobin and lysozyme. Both oligomeric and fibrillar forms of lysozyme were found to exert condensing influence on lipid bilayer structure, with the membrane effects of fibrils being less amenable to modulation by hemoglobin.
在过去的十年中，人们对与许多病理状态相关的特定类型的蛋白质聚集物——淀粉样纤维的结构和毒性特性产生了前所未有的兴趣。在本研究中，荧光光谱技术被用于深入了解淀粉样毒性的膜相关机制。为此，由脂质体和血红蛋白组成的红细胞模型系统受到寡聚体和纤维状溶菌酶的作用。溶菌酶荧光的丙烯酰胺猝灭表明，色氨酸 62 和色氨酸 108 的溶剂可及性在蛋白质纤维化时增加。共振能量转移测量表明血红蛋白和聚集的溶菌酶之间存在直接络合的可能性。使用新型方酸染料 SQ-1 证明，聚集的溶菌酶能够抑制脂质过氧化过程。荧光探针芘、Prodan 和二苯并十六烯被用于表征血红蛋白和溶菌酶的膜修饰特性。发现寡聚体和纤维状形式的溶菌酶都对脂质双层结构具有浓缩影响，而纤维的膜效应不太容易受血红蛋白调节。
