Ikehara M, Kakiuchi N, Fukui T
Nucleic Acids Res. 1978 Sep;5(9):3315-24. doi: 10.1093/nar/5.9.3315.
Poly (2'-deoxy-2'-fluoroinosinic acid) [ poly(If)] was synthesized by polymerization of 2'-deoxy-2'-fluoroinosine 5'-diphosphate catalyzed by Escherichia coli polynucleotide phosphorylase. Although the UV absorption properties of poly(If) closely resembled those of poly(I), thermal melting curves at Na+ concentrations of 0.15M and 0.75M suggested two ordered structures for poly(If) neutral form. CD psectra taken at 0.15M Na+ concentration showed rather larger amplitudes in both a peak at 273 nm and a trough at 246 nm, suggesting rather strong vertical stacking of bases. When complexed with poly(C), poly(If) forms a double-stranded complex, poly(If).poly(C) which has Tm's higher by 10-20 degrees than those of poly(If).poly(C) measured under the same conditions. The CD spectrum of this complex resembled that of poly(I).poly(C). The effect of the fluorine atom at the 2'-position on thermal stability of polynucleotides is discussed.
聚（2'-脱氧-2'-氟肌苷酸）[聚（If）]是由大肠杆菌多核苷酸磷酸化酶催化2'-脱氧-2'-氟肌苷5'-二磷酸聚合而成。尽管聚（If）的紫外吸收特性与聚（I）非常相似，但在0.15M和0.75M的Na +浓度下的热熔解曲线表明聚（If）中性形式有两种有序结构。在0.15M Na +浓度下测得的圆二色光谱在273nm处的峰和246nm处的谷中都显示出相当大的振幅，表明碱基有相当强的垂直堆积。当与聚（C）复合时，聚（If）形成双链复合物聚（If）·聚（C），其熔解温度比在相同条件下测得的聚（I）·聚（C）高10 - 20度。该复合物的圆二色光谱类似于聚（I）·聚（C）的光谱。讨论了2'-位氟原子对多核苷酸热稳定性的影响。
