Lee Bae Wook, Moon Seok Joon, Youn Mi Ryung, Kim Jae Hyung, Jang Ho G, Kim Seog K
Department of Chemistry, Yeungnam University, Dae-dong, Kyoungsan City, Kyoung-buk, 712-749, Republic of Korea.
Biophys J. 2003 Dec;85(6):3865-71. doi: 10.1016/S0006-3495(03)74801-2.
The binding site of Delta- and Lambda-[Ru(phenanthroline)2L]2+ (L being phenanthroline (phen), dipyrido[3,2-a:2'3'-c]phenazine (DPPZ), and benzodipyrido[3,2-a:2'3'-c]phenazine (benzoDPPZ)), bound to poly[d(A-T)2] in the presence and absence of 4',6-diamidino-2-phenylindole (DAPI) was investigated by circular dichroism and fluorescence techniques. DAPI binds at the minor groove of poly[d(A-T)2] and blocks the groove. The circular dichroism spectrum of all Ru(II) complexes are essentially unaffected whether the minor groove of poly[d(A-T)2] is blocked by DAPI or not, indicating that the Ru(II) complexes are intercalated from the major groove. When DAPI and Ru(II) complexes simultaneously bound to poly[d(A-T)2], the fluorescence intensity of DAPI decreases upon increasing Ru(II) complex concentrations. The energy of DAPI at excited state transfers to Ru(II) complexes across the DNA via the Förster type resonance energy transfer. The efficiency of the energy transfer is similar for both [Ru(phen)2DPPZ]2+ and [Ru(phen)2benzoDPPZ]2+ complexes, whereas that of [Ru(phen)3]2+ is significantly lower. The distance between DAPI and [Ru(phen)3]2+ is estimated as 0.38 and 0.64 Förster distance, respectively, for the Delta- and Lambda-isomer.
采用圆二色光谱和荧光技术研究了Δ-和Λ-[Ru（菲咯啉）2L]2+（L为菲咯啉（phen）、二吡啶并[3,2-a:2'3'-c]吩嗪（DPPZ）和苯并二吡啶并[3,2-a:2'3'-c]吩嗪（苯并DPPZ））在存在和不存在4',6-二脒基-2-苯基吲哚（DAPI）的情况下与聚[d（A-T）2]的结合位点。DAPI结合在聚[d（A-T）2]的小沟处并封闭该沟。无论聚[d（A-T）2]的小沟是否被DAPI封闭，所有Ru（II）配合物的圆二色光谱基本不受影响，这表明Ru（II）配合物是从大沟插入的。当DAPI和Ru（II）配合物同时与聚[d（A-T）2]结合时，随着Ru（II）配合物浓度的增加，DAPI的荧光强度降低。激发态下DAPI的能量通过福斯特型共振能量转移穿过DNA转移到Ru（II）配合物上。[Ru（phen）2DPPZ]2+和[Ru（phen）2苯并DPPZ]2+配合物的能量转移效率相似，而[Ru（phen）3]2+的能量转移效率明显较低。对于Δ-和Λ-异构体，DAPI与[Ru（phen）3]2+之间的距离分别估计为0.38和0.64福斯特距离。
