Depew R E, Liu L F, Wang J C
J Biol Chem. 1978 Jan 25;253(2):511-8.
Escherichia coli omega protein is found to form a complex with single-stranded DNA. The complex is stable in buoyant CsCl or Cs2SO4 density gradients. Addition of Mg(II) to the concentrated salt solutions, however, leads to the dissociation of the complex, even in the presence of EDTA in molar excess over Mg(II). The dissociated omega retains its enzymatic activity; the DNA recovered from the dissociated complex is indistinguishable from the original DNA. Exposure of the complex to alkali results in the cleavage of the DNA. This cleavage generates a 3'-hydroxyl DNA terminus, and the omega protein is found linked to the 5'-terminus, presumably covalently. Pronase digestion of the complex results initially in the removal of approximately 30% of the protein. A significant fraction of the residual complex is still stable in concentrated salt solutions, and can be dissociated by Mg(II). Extensive digestion with pronase results in the removal of the protein and the cleavage of the DNA chain.
已发现大肠杆菌ω蛋白与单链DNA形成复合物。该复合物在浮力氯化铯或硫酸铯密度梯度中稳定。然而，向浓盐溶液中添加Mg(II)会导致复合物解离，即使存在摩尔过量于Mg(II)的EDTA也是如此。解离后的ω蛋白保留其酶活性；从解离的复合物中回收的DNA与原始DNA无法区分。将复合物暴露于碱中会导致DNA断裂。这种断裂产生一个3'-羟基DNA末端，并且发现ω蛋白与5'-末端相连，推测是共价连接。用链霉蛋白酶消化复合物最初会去除约30%的蛋白质。残留复合物的很大一部分在浓盐溶液中仍然稳定，并且可以被Mg(II)解离。用链霉蛋白酶进行广泛消化会导致蛋白质去除和DNA链断裂。
