Volkova K D, Kovalska V B, Balanda A O, Vermeij R J, Subramaniam V, Slominskii Yu L, Yarmoluk S M
Institute of Molecular Biology and Genetics, National Academy of Sciences of Ukraine, 150 Zabolotnogo St., 03143 Kyiv, Ukraine.
J Biochem Biophys Methods. 2007 Aug 1;70(5):727-33. doi: 10.1016/j.jbbm.2007.03.008. Epub 2007 Mar 30.
We ascertained the ability to detect fibrillar beta-lactoglobulin (BLG) of a series of mono-, tri-, penta-, and heptamethinecyanines based on benzothiazole and benzimidazole heterocycles, and of benzothiazole squaraine. Fluorescence properties of these cyanine dyes were measured in the unbound state and in the presence of monomeric and fibrillar BLG and compared with those for the commercially available benzothiazole dye Thioflavin T. The correlation between the chemical nature of the dye molecules and the ability of dyes to bind aggregated proteins was established. We found that meso-substituted cyanines with amino substituents in heterocycle in contrast to the corresponding unsubstituted dyes have a binding preference to fibrillar BLG and a noticeable fluorescence response in the presence of the aggregated protein. For the squaraines and benzimidazole penthamethinecyanines studied, fluorescence emission increased both in the presence of native and fibrillar protein. The trimethinecyanines T-49 and SH-516 exhibit specifically increased fluorescence in the presence of fibrillar BLG. These dyes demonstrated the same or higher emission intensity and selectivity to aggregated BLG as Thioflavin T, and are proposed for application in selective fluorescent detection of aggregated proteins.
我们测定了一系列基于苯并噻唑和苯并咪唑杂环的单甲川、三甲川、五甲川和七甲川菁以及苯并噻唑方酸菁检测纤维状β-乳球蛋白（BLG）的能力。在未结合状态以及存在单体和纤维状BLG的情况下测量了这些菁染料的荧光特性，并与市售苯并噻唑染料硫黄素T的荧光特性进行了比较。建立了染料分子的化学性质与染料结合聚集蛋白能力之间的相关性。我们发现，与相应的未取代染料相比，在杂环中带有氨基取代基的中位取代菁对纤维状BLG具有结合偏好，并且在存在聚集蛋白的情况下有明显的荧光响应。对于所研究的方酸菁和苯并咪唑五甲川菁，在天然蛋白和纤维状蛋白存在时荧光发射均增加。三甲川菁T-49和SH-516在纤维状BLG存在时表现出特异性增强的荧光。这些染料对聚集的BLG表现出与硫黄素T相同或更高的发射强度和选择性，并被建议用于聚集蛋白的选择性荧光检测。
