Howard F B, Frazier J, Miles H T
Proc Natl Acad Sci U S A. 1969 Oct;64(2):451-8. doi: 10.1073/pnas.64.2.451.
The carbonyl stretching vibrations of G and C residues undergo frequency changes when a helical complex is formed from nonordered G and C components. We have prepared a series of two-stranded G:C helices having chemical and isotopic ((18)O) substitutions which lead to variation of the observed vibrational frequencies. Infrared spectra of these helices clearly demonstrate that vibrational coupling occurs between the guanine and cytosine residues in the helix. As a result of this coupling through the hydrogen bonds, the two carbonyl bands undergo frequency shifts of equal magnitude and opposite sign, with mixing of G and C character in the observed interacted vibrations.
当由无序的G和C组分形成螺旋复合物时，G和C残基的羰基伸缩振动会发生频率变化。我们制备了一系列具有化学和同位素（(18)O）取代的双链G:C螺旋，这导致了观察到的振动频率发生变化。这些螺旋的红外光谱清楚地表明，螺旋中的鸟嘌呤和胞嘧啶残基之间发生了振动耦合。由于通过氢键的这种耦合，两个羰基带发生大小相等、符号相反的频率位移，在观察到的相互作用振动中G和C特征发生混合。
