Winkle S A, Tinoco I
Biochemistry. 1979 Sep 4;18(18):3833-9. doi: 10.1021/bi00585a001.
The interactions of 4-nitroquinoline 1-oxide (NQO), a potent mutagen and carcinogen, with several self- and non-self-complementary deoxydinucleotides were probed by using absorption spectra of the charge transfer bands and 1H and 13C NMR spectra. Absorption spectra were analyzed by using Benesi-Hildebrand-type equations to yield stoichiometries and equilibrium constants of complex formation. Non-self complementary dimers form weak l:1 complexes [dpTpG:NQO, K(25 degrees C) = 22 M-1] while self-complementary dimers form strong 2:1 complexes [dpCpG)2:NQO, K(25 degrees C) = 2.2 X 10(4) M-2]. A mixture of dpTpG and dpCpA with NQO gives a 2:1 complexes [dpCpG)2:NQO, K(25 degrees C) = 2.2 X 10(4) M-2]. A mixture of dpTpG and dpCpA, K(25 degrees C) = 8.6 X 10(3) M-2]. Analyses of the changes in 13C and 1H NMR chemical shifts with complex formation gave approximate orientations for the intercalation of NQO with self-complementary dimer minihelixes. In the (dpCpG)2:NQO and (dpGpC)2:NQO complexes, the NO2 group of NQO probably lies in the major grove and the NO2, NO containing NQO ring is stacked near the purine imidazole ring. In the (dpTpA)2:NQO and (dpApT)2NQO complexes, the NO2 seems to project into the minor grove and the NQO benzenoid ring is over the purine imidazole ring.
4-硝基喹啉1-氧化物（NQO）是一种强效诱变剂和致癌物，通过电荷转移带的吸收光谱以及1H和13C NMR光谱研究了它与几种自身互补和非自身互补脱氧二核苷酸的相互作用。利用贝内西-希尔德布兰德型方程对吸收光谱进行分析，以得出配合物形成的化学计量比和平衡常数。非自身互补二聚体形成弱的1:1配合物[dpTpG:NQO，K（25℃） = 22 M-1]，而自身互补二聚体形成强的2:1配合物[dpCpG)2:NQO，K（25℃） = 2.2×10(4) M-2]。dpTpG和dpCpA与NQO的混合物形成2:1配合物[dpCpG)2:NQO，K（25℃） = 2.2×10(4) M-2]。dpTpG和dpCpA的混合物，K（25℃） = 8.6×10(3) M-2]。通过分析13C和1H NMR化学位移随配合物形成的变化，得出了NQO与自身互补二聚体小螺旋插入的近似取向。在(dpCpG)2:NQO和(dpGpC)2:NQO配合物中，NQO的NO2基团可能位于大沟中，含NO2、NO的NQO环堆叠在嘌呤咪唑环附近。在(dpTpA)2:NQO和(dpApT)2NQO配合物中，NO2似乎伸向小沟，NQO苯环在嘌呤咪唑环上方。
