Molineux I J, Gefter M L
Proc Natl Acad Sci U S A. 1974 Oct;71(10):3858-62. doi: 10.1073/pnas.71.10.3858.
The E. coli DNA binding protein reduces the activity of the single-strand-specific nucleases associated with all three DNA polymerases known in E. coli. A slight excess of binding protein over that required to saturate the DNA template leads to total inhibition of activity of the 3' --> 5' nucleases associated with DNA polymerases I and III, but restores maximum activity of the DNA polymerase II-associated nuclease. The binding protein forms a specific complex with DNA polymerase II in the absence of DNA, and it is this complex that degrades a DNA.binding protein complex. Binding protein also facilitates the binding of DNA polymerase II to single-stranded DNA, whereas the binding to DNA of DNA polymerase I is inhibited. These data may explain the specificity with which the binding protein enhances the synthetic ability of DNA polymerase II.
大肠杆菌DNA结合蛋白会降低与大肠杆菌中已知的所有三种DNA聚合酶相关的单链特异性核酸酶的活性。结合蛋白的量略超过使DNA模板饱和所需的量时,会导致与DNA聚合酶I和III相关的3'→5'核酸酶的活性完全受到抑制,但会恢复与DNA聚合酶II相关的核酸酶的最大活性。在没有DNA的情况下,结合蛋白会与DNA聚合酶II形成特定的复合物,正是这种复合物会降解DNA结合蛋白复合物。结合蛋白还促进DNA聚合酶II与单链DNA的结合,而DNA聚合酶I与DNA的结合则受到抑制。这些数据可能解释了结合蛋白增强DNA聚合酶II合成能力的特异性。