Daban J R, Samsó M, Bartolomé S
Departament de Bioquímica i Biologia Molecular, Facultat de Ciències, Universitat Autònoma de Barcelona, Spain.
Anal Biochem. 1991 Dec;199(2):162-8. doi: 10.1016/0003-2697(91)90084-7.
Our results show that the noncovalent dye 9-diethylamino-5H-benzo[alpha]phenoxazine-5-one (Nile red) can be used as a fluorescent probe to study the hydrophobic properties of proteins associated with the anionic detergent sodium dodecyl sulfate (SDS). Nile red can interact with both SDS micelles and protein-SDS complexes. The enhancement of Nile red fluorescence observed with diverse types of proteins occurs at SDS concentrations lower than the critical micelle concentration of this detergent. This is also observed using the covalent fluorophore rhodamine B isothiocyanate. Additional results obtained in studies in solution show that the fluorescence intensity and the spectral characteristics of Nile red associated with different proteins complexed with SDS are very similar. These spectroscopic similarities are probably related to the equivalent synchrotron X-ray scattering results found for various protein-SDS complexes in solution. The scattering results suggest that SDS induces the formation of complexes in which the basic structural properties are independent of the different initial structures of native proteins. We speculate that Nile red is bound to regions with equivalent hydrophobic characteristics located in the uniform structures produced by the association of SDS with proteins.
我们的结果表明，非共价染料9-二乙氨基-5H-苯并[α]吩恶嗪-5-酮（尼罗红）可作为荧光探针，用于研究与阴离子洗涤剂十二烷基硫酸钠（SDS）相关的蛋白质的疏水特性。尼罗红可与SDS胶束和蛋白质-SDS复合物相互作用。在低于该洗涤剂临界胶束浓度的SDS浓度下，观察到不同类型蛋白质的尼罗红荧光增强。使用共价荧光团异硫氰酸罗丹明B也观察到了这一点。溶液研究中获得的其他结果表明，与不同SDS复合蛋白质相关的尼罗红的荧光强度和光谱特征非常相似。这些光谱相似性可能与溶液中各种蛋白质-SDS复合物的等效同步加速器X射线散射结果有关。散射结果表明，SDS诱导形成复合物，其中基本结构特性与天然蛋白质的不同初始结构无关。我们推测尼罗红与SDS与蛋白质结合产生的均匀结构中具有等效疏水特性的区域结合。
