Kang Jung Sook, Piszczek Grzegorz, Lakowicz Joseph R
Department of Oral Biochemistry and Molecular Biology, College of Dentistry, Pusan National University, Pusan 602-739, Korea.
Institute of Experimental Physics, University of Gdańsk, ul. Wita Stwosza 57, 80-952, Gdańsk, Poland.
J Fluoresc. 2002 Mar;12(1):97-103. doi: 10.1023/A:1015375622992.
We report observation of high quantum yield, long-lifetime fluorescence from a red dye BO-PRO-3 excited by resonance energy transfer (RET). The acceptor fluorescence was highly enhanced upon binding to the donor-labeled DNA. A ruthenium complex (Ru) was chosen as a donor in this system because of its long fluorescence lifetime. Both donor and acceptor were non-covalently bound to DNA. Emission from the donor-acceptor system (DA) at wavelengths exceeding 600 nm still preserves the long-lifetime component of the Ru donor, retaining average fluorescence lifetimes in the range of 30-50 ns. Despite the low quantum yield of the Ru donor in the absence of acceptor, its overall quantum yield of the DA pair was increased by energy transfer to the higher quantum yield acceptor BO-PRO-3. The wavelength-integrated intensity of donor and acceptor bound to DNA was many-fold greater than the intensity of the donor and acceptor separately bound to DNA. The origin of this effect is due to an efficient energy transfer from the donor, competing with non-radiative depopulation of the donor excited state. The distinctive features of DA complexes can be used in the development of a new class of engineered luminophores that display both long lifetime and long-wavelength emission. Similar DA complexes can be applied as proximity indicators, exhibiting strong fluorescence of adjacently located donors and acceptors over the relatively weak fluorescence of separated donors and acceptors.
我们报道了通过共振能量转移（RET）激发的红色染料BO - PRO - 3产生的高量子产率、长寿命荧光的观测结果。受体荧光在与供体标记的DNA结合后得到高度增强。在该系统中选择钌配合物（Ru）作为供体是因为其荧光寿命长。供体和受体均非共价结合到DNA上。供体 - 受体系统（DA）在超过600 nm波长处的发射仍保留了Ru供体的长寿命成分，平均荧光寿命保持在30 - 50 ns范围内。尽管在没有受体的情况下Ru供体的量子产率较低，但通过能量转移到更高量子产率的受体BO - PRO - 3，DA对的整体量子产率得以提高。与DNA结合的供体和受体的波长积分强度比分别与DNA结合的供体和受体的强度大很多倍。这种效应的起源是由于供体的有效能量转移，与供体激发态的非辐射去极化相竞争。DA复合物的独特特性可用于开发一类新型的工程发光体，其兼具长寿命和长波长发射。类似的DA复合物可作为邻近指示剂，与分离的供体和受体相对较弱的荧光相比，相邻定位的供体和受体表现出强荧光。
