孟加拉玫瑰红对pBR322 DNA中单链断裂的光敏化作用。

Photosensitization of single-strand breaks in pBR322 DNA by rose bengal.

作者信息

Ciulla T A, Van Camp J R, Rosenfeld E, Kochevar I E

出版信息

Photochem Photobiol. 1989 Mar;49(3):293-8. doi: 10.1111/j.1751-1097.1989.tb04109.x.

DOI:10.1111/j.1751-1097.1989.tb04109.x

Abstract

Rose bengal photosensitized the formation of frank single-strand breaks (SSBs) in double-stranded, supercoiled pBR322 DNA as measured by neutral agarose electrophoresis. The yield of SSBs followed first order kinetics with respect to light fluence and dye concentration. The efficiency of cleavage was more than 20 times greater in an argon atmosphere than in an oxygen atmosphere. The quantum yield in an air atmosphere was 1.7 (+/- 0.3) X 10(-8). Sodium azide quenched the cleavage more efficiently in an oxygen atmosphere than when the oxygen concentration was reduced. Isopropanol and mannitol were poor quenchers; ribose-5-phosphate and guanosine-5'-monophosphate did not quench the cleavage. Substituting D2O for H2O increased the yield of SSBs in both oxygen and oxygen-depleted atmospheres. The results are consistent with initiation of cleavage by reaction of the triplet state of rose bengal (or a radical derived from it) with DNA. In the presence of oxygen, an additional mechanism is introduced.

摘要

孟加拉玫瑰红可使双链超螺旋pBR322 DNA形成明显的单链断裂（SSB），这可通过中性琼脂糖电泳来测定。单链断裂的产量遵循关于光通量和染料浓度的一级动力学。在氩气气氛中，切割效率比在氧气气氛中高20倍以上。在空气气氛中的量子产率为1.7（±0.3）×10⁻⁸。叠氮化钠在氧气气氛中比在氧气浓度降低时更有效地淬灭切割。异丙醇和甘露醇是较差的淬灭剂；5-磷酸核糖和5'-单磷酸鸟苷不能淬灭切割。用重水代替水可增加在氧气和贫氧气氛中SSB的产量。结果与孟加拉玫瑰红（或其衍生的自由基）的三重态与DNA反应引发切割一致。在有氧气存在的情况下，引入了一种额外的机制。