Hübscher U, Kornberg A
Proc Natl Acad Sci U S A. 1979 Dec;76(12):6284-8. doi: 10.1073/pnas.76.12.6284.
The delta subunit of DNA polymerase III holoenzyme has been purified extensively with an assay for phi X174 DNA synthesis using core (pol III) and beta and gamma subunits. Either the purified delta subunit or the purified DNA polymerase III holoenzyme can complement a defective enzyme fraction from the conditional replication mutant SG133 described by Sevastopoulos et al. [Sevastopoulas, C.G., Wehr, C.T. & Glaser, D. A. (1977) Proc. Natl. Acad. Sci. USA 74, 3485-3489]. It has been established by Henson et al. [Henson, J.M., Chu, H., Irwin, C.A. & Walker, J.R. (1979) Genetics 92, 1,41-1059] that SG133 has two temperature-sensitive mutations, called dnaX and dnaY. The crude enzyme source from dnaX can be complemented by the delta subunit and by DNA polymerase III holoenzyme. By contrast, the core DNA polymerase III and the beta and gamma subunits are unable to complement this defective enzyme fraction. Thus, the delta subunit of DNA polymerase III holoenzyme appears to be the dnaX gene product of Escherichia coli.
利用核心（pol III）、β和γ亚基对phi X174 DNA合成的检测方法，已对DNA聚合酶III全酶的δ亚基进行了广泛纯化。纯化的δ亚基或纯化的DNA聚合酶III全酶都可以补充Sevastopoulos等人描述的条件复制突变体SG133中的缺陷酶部分[Sevastopoulas, C.G., Wehr, C.T. & Glaser, D. A. (1977) Proc. Natl. Acad. Sci. USA 74, 3485 - 3489]。Henson等人[Henson, J.M., Chu, H., Irwin, C.A. & Walker, J.R. (1979) Genetics 92, 1,41 - 1059]已经确定SG133有两个温度敏感突变，分别称为dnaX和dnaY。来自dnaX的粗酶源可以被δ亚基和DNA聚合酶III全酶补充。相比之下，核心DNA聚合酶III以及β和γ亚基无法补充这种缺陷酶部分。因此，DNA聚合酶III全酶的δ亚基似乎是大肠杆菌的dnaX基因产物。
