Grandgenett D P, Golomb M, Vora A C
J Virol. 1980 Jan;33(1):264-71. doi: 10.1128/JVI.33.1.264-271.1980.
Partial chymotryptic digestion of purified avian myeloblastosis virus alpha beta DNA polymerase resulted in the activation of a Mg2+-dependent DNA endonuclease activity. Incubation of the polymerase-protease mixture in the presence of super-coiled DNA and Mg2+ permitted detection of the cleaved polymerase fragment possessing DNA nicking activity. Protease digestion conditions were established permitting selective cleavage of beta to alpha, which contained DNA polymerase and RNase H activity and to a family of polypeptides ranging in size from 30,000 to 34,000 daltons. These latter beta-unique fragments were purified by polyuridylate-Sepharose 4B chromatography and were shown to contain both DNA binding and DNA endonuclease activities. We have demonstrated that this group of polymerase fragments derived by chymotryptic digestion of alpha beta DNA polymerase is similar to the in vivo-isolated avian myeloblastosis virus p32pol in size, sequence, and DNA endonuclease activity.
对纯化的禽成髓细胞瘤病毒αβ DNA聚合酶进行部分胰凝乳蛋白酶消化，导致一种Mg2+依赖的DNA内切酶活性被激活。在超螺旋DNA和Mg2+存在的情况下，将聚合酶-蛋白酶混合物进行温育，可检测到具有DNA切口活性的切割后的聚合酶片段。确定了蛋白酶消化条件，可实现对β至α的选择性切割，α含有DNA聚合酶和RNase H活性，以及一系列大小在30,000至34,000道尔顿之间的多肽。这些后一种β特有的片段通过聚尿苷酸-琼脂糖4B层析进行纯化，并显示含有DNA结合和DNA内切酶活性。我们已经证明，通过胰凝乳蛋白酶消化αβ DNA聚合酶得到的这一组聚合酶片段在大小、序列和DNA内切酶活性方面与体内分离的禽成髓细胞瘤病毒p32pol相似。
