Johnston B H, Kung A H, Moore C B, Hearst J E
Biochemistry. 1981 Feb 17;20(4):735-8. doi: 10.1021/bi00507a011.
If a mixture of T4 deoxyribonucleic acid (DNA) and 4'-(aminomethyl)-4,5',8-trimethylpsoralen is irradiated with two closely spaced pulses of long-wave UV laser light, the resulting cross-linking is dependent on the time delay between the pulses. As the delay lengthens to 1 mus, a rise in the number of cross-links is observed which follows first-order kinetics. This delay, the time required for most monoadducts to be able to absorb a second photon and thereupon form a cross-link, is interpreted in terms of a conformational change in the DNA at the psoralen intercalation site which may occur upon monoadduct formation.
如果用两个间隔很近的长波紫外激光脉冲照射T4脱氧核糖核酸（DNA）与4'-（氨甲基）-4,5',8-三甲基补骨脂素的混合物，那么由此产生的交联作用取决于脉冲之间的时间延迟。当延迟延长至1微秒时，会观察到交联数量增加，且符合一级动力学。这种延迟，即大多数单加合物能够吸收第二个光子并进而形成交联所需的时间，可根据补骨脂素嵌入位点处DNA的构象变化来解释，这种构象变化可能在单加合物形成时发生。
