Omar Salama, Eriksson Leif A
Orebro Life Science Center, School of Science and Technology, Orebro University, 701 82, Orebro, Sweden.
Photochem Photobiol Sci. 2009 Aug;8(8):1179-86. doi: 10.1039/b905147c. Epub 2009 Jul 6.
A theoretical investigation of the formation and spectroscopic properties of the furan and pyrone monoadducts between the photosensitizer khellin and DNA base thymine is reported. The thermal reaction pathways involve very high barriers, whereas the excited state surfaces display low barriers in regions leading to the ground state TS structures and potential wells at the ground state TS geometries. Computed UV absorption spectra are interpreted with the support of molecular orbital calculations, and the role of solvent effects on the spectra is discussed. The red-shift in the khellin spectra upon intercalation in DNA is excellently reproduced by the computational methodology, as is the solvent induced spectral shift. The data also provides an explanation to why khellin predominantly forms furan monoadducts in DNA, as opposed to the closely related psoralen compounds.
报道了关于光敏剂凯林与DNA碱基胸腺嘧啶之间呋喃和吡喃酮单加合物的形成及其光谱性质的理论研究。热反应途径涉及非常高的势垒，而激发态表面在导致基态过渡态结构的区域以及基态过渡态几何结构处的势阱中显示出低势垒。在分子轨道计算的支持下对计算得到的紫外吸收光谱进行了解释，并讨论了溶剂效应对光谱的作用。通过计算方法出色地再现了凯林在插入DNA时光谱的红移以及溶剂诱导的光谱位移。这些数据还解释了为什么与密切相关的补骨脂素化合物不同，凯林在DNA中主要形成呋喃单加合物。
