The ultraviolet transitions of the ethidium cation
The ultraviolet transitions of the ethidium cation
复制标题
乙锭阳离子的紫外跃迁
DOI：
10.1002/bip.1975.360140619
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发表时间：
1975
期刊：
影响因子：
2.9
通讯作者：
R. Jacobs
中科院分区：
文献类型：
--
作者：
B. Hudson;R. Jacobs
最近，人们对乙锭阳离子的电子光谱产生了兴趣，因为人们希望了解乙锭-DNA复合物的圆二色性3f 4和能量转移性质5。从阐明大荧光增强的机制的角度来看，也感兴趣的测定激发态的能量的乙锭，这是观察到当乙锭结合到DNA。溴化乙锭在水中的吸收光谱包含一个可见带（Amax 480 nm，emax 5300），一个位于318 nm的肩峰和一个位于285 nm的非常强的跃迁（em，50，000），这将被称为主要的紫外跃迁。在210 nm（e，40，000）处有另一个强跃迁。该通信包括在343 nm处的近紫外跃迁的识别，该跃迁在吸收光谱中未观察到，但在磁性圆二色性（MCD）光谱中清楚地观察到。这可能是已在乙锭-DNA复合物的CD和电二色性光谱中检测到的跃迁。一个有趣的相关性的紫外波段的乙锭阳离子与菲的跃迁，这有重要的意义的极化的乙锭跃迁和预期的三重态能量。
There has been recent interest in the electronic spectroscopy of the ethidium cationltz because of a desire to understand the circular dichroism3f4 and energy-transfer properties5 of the ethidium-DNA complex. A determination of the energies of the excited states of ethidium is also of interest from the point of view of elucidating the mechanism of the large fluorescence enhancement, which is observed when ethidium binds to DNA. 6 This was the primary motivation for this study.The absorption spectrum of ethidium bromide in water contains a visible band (Amax 480 nm, emax 5300), a shoulder at 318 nm, and a very strong transition at 285 nm (em,, 50,000), which will be referred to as the main uv transition. There is another strong transition at 210 nm (e, 40,000). This communication consists of the identification of a near-uv transition at 343 nm, which is not observed in the absorption spectrum but which is clearly observed in the magnetic circular dichroism (MCD) spectrum. This is probably the transition that has been detected in the CD and electric dichroism spectra of the ethidium-DNA complex. An interesting correlation of the uv bands of the ethidium cation with the transitions of phenanthrene is also given, which has important implications for the polarization of the ethidium transitions and the expected energies of triplet states.