Title: DNA Polymerases II and III of Escherichia coli
Abstract: This chapter deals with the recent developments concerning the isolation and characterization of DNA polymerases II and III of Escherichia coli. Genetic and physiological experiments designed to elucidate the biological function of these enzymes are also discussed. The chapter explores the properties of the first DNA polymerase to be isolated from E. coli, DNA polymerase. The isolation of a mutant of E. coli defective in DNA polymerase I activity (PolA1-) provided the basis for several investigations into the nature of the enzymatic mechanism of DNA replication in such cells. After the isolation of the PolA1- mutant, it was generally assumed, since no other polymerase had yet been discovered in E. coli, that either residual amounts of DNA polymerase I or some yet undiscovered polymerase with perhaps unusual requirements for activity provided the enzymatic activity required for DNA replication. Initially, we described an enzyme activity in PolA1- cells that catalyzed the synthesis of DNA. This activity was resistant to antiserum capable of inactivating DNA polymerase I. It was also discovered that there indeed exists another DNA polymerase activity in E. coli and the isolation and purification of this enzyme, DNA polymerase II, from cells lysed after toluene or detergent treatment and by more conventional means were reported. No strong evidence yet exists that the preparation of this enzyme requires any unconventional procedures; its low activity compared to that of DNA polymerase I probably accounts for the fact that it was previously unnoticed in wild-type E. coli.
Publication Year: 1974
Publication Date: 1974-01-01
Language: en
Type: review
Indexed In: ['crossref', 'pubmed']
Access and Citation
Cited By Count: 32
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