McHenry C, Kornberg A
J Biol Chem. 1977 Sep 25;252(18):6478-84.
DNA polymerase III holoenzyme has been purified from Escherichia coli HMS-83, using, as an assay, the conversion of coliphage G4 single-stranded DNA to the duplex replicative form. The holoenzyme consists of at least four different subunits: alpha, beta, gamma, and delta of 140,000, 40,000, 52,000, and 32,000 daltons, respectively. The alpha subunit is DNA polymerase III, the dnaE gene product. The holoenzyme has been resolved by phosphocellulose chromatography into an alpha - gamma - delta complex and a subunit beta (copolymerase III*); neither possesses detectable activity in the G4 system but together reconstitute holoenzyme-like activity. The alpha - gamma - delta complex has been further resolved to yield a gamma - delta complex which reconstitutes alpha - gamma - delta activity when added to DNA polymerase III. The gamma - delta complex contains a product of the dnaZ gene and has been purified from a strain which contains a ColE1-dnaZ hybrid plasmid.
已从大肠杆菌HMS - 83中纯化出DNA聚合酶III全酶，采用的分析方法是将噬菌体G4单链DNA转化为双链复制形式。全酶至少由四种不同的亚基组成：分别为140,000、40,000、52,000和32,000道尔顿的α、β、γ和δ亚基。α亚基是DNA聚合酶III，即dnaE基因产物。全酶通过磷酸纤维素色谱法分离为α - γ - δ复合物和亚基β（共聚合酶III*）；在G4系统中两者均不具有可检测的活性，但一起可重建类似全酶的活性。α - γ - δ复合物已进一步分离，得到γ - δ复合物，当将其添加到DNA聚合酶III中时可重建α - γ - δ活性。γ - δ复合物包含dnaZ基因的产物，并且已从含有ColE1 - dnaZ杂种质粒的菌株中纯化得到。
