García E, Ronda C, López R
Eur J Biochem. 1979 Nov 1;101(1):59-64. doi: 10.1111/j.1432-1033.1979.tb04216.x.
The properties of Dp-4 phage and its DNA have been studied. The phage has a polyhedral head of 60 nm diameter, a tail 155 nm long and a buoyant density in CsCl of 1.48 g/cm3. Analysis by acrylamide gel electrophoresis indicates the presence of five polypeptides. Dp-4 DNA has a molecular weight of 37 x 10(6), a melting point of 83.5 degrees C (when dissolved in 0.15 M NaCl/0.015 M sodium citrate, pH 7.0) and a G + C content of about 33%. Denaturation of DNA yields two strands of different buoyant density in a neutral CsCl gradient. The interaction of poly(U, G) with the heavy strand strongly enhances its density and allows the preparative separation of both strands. Native Dp-4 DNA has unusual physical properties: abnormally low buoyant densities both in CsCl (1.666 g/cm3) and in Cs2SO4 (1.410 g/cm3) (which do not correspond to the value predictable from the G + C content of the DNA), and a high thermal stability at low ionic strength.
已对Dp - 4噬菌体及其DNA的特性进行了研究。该噬菌体有一个直径为60纳米的多面体头部、一条155纳米长的尾部，在氯化铯中的浮力密度为1.48克/立方厘米。丙烯酰胺凝胶电泳分析表明存在五种多肽。Dp - 4 DNA的分子量为37×10⁶，熔点为83.5℃（当溶解于0.15M氯化钠/0.015M柠檬酸钠，pH 7.0时），鸟嘌呤与胞嘧啶（G + C）含量约为33%。DNA变性后在中性氯化铯梯度中产生两条浮力密度不同的链。聚（尿嘧啶，鸟嘌呤）[poly(U, G)]与重链的相互作用强烈提高了其密度，并使得两条链得以制备性分离。天然Dp - 4 DNA具有不同寻常的物理特性：在氯化铯（1.666克/立方厘米）和硫酸铯（1.410克/立方厘米）中的浮力密度异常低（这与根据DNA的G + C含量预测的值不相符），并且在低离子强度下具有高热稳定性。
