聚腺嘌呤核苷酸(PolyA)水化过程的傅里叶变换红外光谱研究 Ⅰ. 静态水化过程的特性

在静态平衡条件下, 应用FT-IR和减差光谱技术系统地测定了Poly A薄膜在温度为25±1 ℃、相对湿度从0％到100％的不同情况下的吸收光谱, 波段范围为4000-800 cm~(-1)。根据红外光谱的峰位和强度的变化, 证实了Poly A的水化作用主要发生在碱基中的-NH_2基团和磷酸根基团上。其中-NH_2的光谱强度在相对湿度低于30％时就有明显变化, 是水化较强的基团之一; 而P=0的峰位移最大, 并且在高湿度时出现两个振动频率, 说明有两种不同的水化状态。在水化过程中, 水峰的峰位也有较大变化, 并分裂为多重峰。

FOURIER TRANSFORM INFRARED STUDY ON THE HYDRATION OF POLYADENYLIC ACID (POLY A) I. STATIC HYDRATION PROPERTIES

By means of FT-IR and subtraction techniques the absorption spectra of Poly A film have been studied systematically in the 4000 to 800 cm~1 region at (25±1) ℃ as a function of relative humidity (from 0％ to 100％) at static equilibrium. According to the peak position and intensity changes of infrared bands it proves that the hydration of Poly A has happened mainly on the-NH_2 group of pbase, -PO_2 group and ribose ring; and the possible hydrating sequence is as shown in Fig.9. In comparision with the previous investigators~2] many new informations are obtained. First, the —NH_2 band (～1712 cm~(-1)) shows strongest variation in intensity at RH≤30% (Fig.4) and obvious frequency shift at RH≥75% (Fig.6). So it is one of the strongest hydrating sites. Then, the P=0 band (～1240 cm~(-1)) does not only behave as a 20 cm~(-1) frequency shift pointed out by Falk but splits into two peaks and coexists at high relative humidity (see Fig.3 and Fig.5). Besides, the spectra of water molecule also varies obviously and splits into multiple peaks during hydration (Fig.7). This indicates that the molecules bonding to Poly A have different structure status.