Colmenarejo G, Bárcena M, Gutiérrez-Alonso M C, Montero F, Orellana G
Department of Biochemistry and Molecular Biology I, Complutense University of Madrid, Spain.
FEBS Lett. 1995 Nov 6;374(3):426-8. doi: 10.1016/0014-5793(95)01150-d.
A new type of DNA-intercalating viologen dications, derived from the N,N'-dialkyl-6-(2-pyridyl)phenanthridine structure (in which dialkyl is -CH2CH2-,-CH2CH2CH2-, or (-CH3)2, abbreviated dq2pyp, dq3pyp, and Me2pyp, respectively), are able to produce frank strand breaks in supercoiled plasmid DNA upon irradiation with visible light. The amount of photocleavage is similar for the three drugs. The observed DNA photosensitization appears to follow a single-strand cleavage model, as shown by a kinetic analysis of the reaction with dq2pyp. The photodynamic action of the drugs seems to be initiated by a light-induced electron transfer reaction from the nucleobases, given the singlet excited-state redox potentials (ca. + 2.1 V vs. SHE) and the low quantum yields of singlet molecular oxygen production of the drugs (0.1-0.2 in aerated D2O).
一种新型的DNA嵌入紫精双阳离子，其衍生自N，N'-二烷基-6-（2-吡啶基）菲啶结构（其中二烷基为-CH2CH2-、-CH2CH2CH2-或（-CH3）2，分别缩写为dq2pyp、dq3pyp和Me2pyp），在可见光照射下能够在超螺旋质粒DNA中产生明显的链断裂。这三种药物的光切割量相似。观察到的DNA光致敏作用似乎遵循单链切割模型，如与dq2pyp反应的动力学分析所示。考虑到药物的单重激发态氧化还原电位（相对于标准氢电极约为+2.1 V）以及药物在充氧重水中产生单重态分子氧的低量子产率（0.1-0.2），药物的光动力作用似乎是由来自核碱基的光诱导电子转移反应引发的。
