The interaction of ruthenium polypyridyl complex with DNA has been studied by isothermal titration calorimetry (ITC). The results show that complex [Ru(phen)2PMIP]2+ {phen=1,10-phenanthroline, PMIP=2-(4-methylphenyl)imidazo1,10-phenanthroline} interacts with calf thymus DNA (CT DNA) in terms of a model for a single set of identical sites through intercalation. The results are in agreement with our previous observations from spectroscopic methods and viscosity measurements. In addition, the results further show that the driving force for DNA binding with the complex is mainly driven by the enthalpy changes, and the contribution from the entropy changes to this driving force is negligible.
血凝素基因（ha）突变的麻疹病毒毒株失去了感染其敏感宿主Vero细胞的能力,但可以感染绒猴-B类淋巴母细胞系B95a,推测在B95a细胞上有这类麻疹病毒毒株的新的受体分子.为此,采用酵母双杂交系统,从B95a细胞cDNA文库中筛选、克隆了一个上述麻疹病毒血凝素蛋白（Ha蛋白）的相互作用蛋白基因——bip（b-lymphoblastoid interaction protein of marmoset）.该基因cDNA全长1540个碱基对,包含1011个碱基对的可读框,推测编码337个氨基酸组成的蛋白（Bip）.推导的氨基酸一级结构表明:Bip蛋白含有一个疏水跨膜区和一个疏水引导区.缺失突变体研究表明,Bip蛋白跨膜区缺失不影响Bip蛋白与Ha蛋白的相互作用.在麻疹病毒非允许细胞CHO（中国仓鼠卵巢细胞）中表达bip基因,结果证明CHO/Bip由非允许细胞变成了对上述麻疹病毒敏感的允许细胞,即表达有Bip蛋白的CHO细胞可以被麻疹病毒吸附、感染.证明bip是位于绒猴-B类淋巴母细胞中的麻疹病毒新的细胞受体基因.
