Keywords: 
• 核酸、藏红T、长距组装、吸收光谱、荧光光谱、共振光散射光谱

Abstract: The long-range assembly of Safranine T(ST) on the molecular surfaces of nucleic acids is characterized by measuring resonance light scattering (RLS), electronic absorption and fluorescence emission. It was found that the long range assembly of ST on the molecular surfaces of nucleic acids at pH 7.05 and ionic strength 0.004 5, depending on the molar ratio of ST to nucleic acids, involves two processes. When the molar ratio of ST to nucleic acids is larger than 1.33, the long range assembly of ST on the molecular surface of nucleic acids occurs, which characterizes hypsochromicly hypochromic effect, fluorescence quenching, and three strong enhanced peaks of resonance light-scattering at 328.0, 472.0 and 572.0 nm. When the molar ratio is lower than 1.33, however, the disassociation of the species of the long range assembly of ST takes places, which characterizes bathochromically hypochromic effect, fluorescence quenching, and weak enhanced resonance light-scattering. Intercalative binding of ST in to DNA takes place in the process of the disassociation of the assembly species.