Inability of Escherichia coliB to Incorporate Added Deoxycytidine, Deoxyadenosine, and Deoxyguanosine into DNA

Abstract

It is known that Escherichia coli can incorporate labeled thymidine into its DNA, but it has not been previously possible to measure the incorporation of the other deoxyribonuclcosides deoxycytidine, deoxyadenosine, and deoxyguanosine because of degradation of these com-The present experiments utilize a mutant of E . coli B lacking deoxyribonucleoside-catabolizing enzymes. This strain, OK441, has mutations affecting the following enzymes : thymidine phosphorylase, purine nucleoside phosphorylase, cytidine deaminase, and adenosine deaminase.The results with OK441 show that E . coZi, in contrast t o lactobacilli and mammalian cells, does not incorporate any deoxyribonucleoside other than thymidine into its DNA. E . coli may be unable t o phosphorylate deoxycytidine, deoxyadenosine, and deoxyguanosine. I n agreement with this suggestion, only thymidine kinase but no other deoxyribonucleotide kinase could be detected in extracts of OK441. pounds.When radioactively labeled thymidine is added to the medium of growing Escherichia coli, label is incorporated into DNA. With [S]. It contains mutations affecting the cytidine and adenosine deaminases, which degrade deoxycytidine and deoxyadenosine, respectively. It also contains mutations affecting thymidine phosphorylase, which degrades thymidine, and purine nucleoside phosphorylase which attacks deoxyadenosine and deoxyguanosine.The experiments demonstrate that thymidine is the only deoxyribonucleoside that is incorporated at a n appreciable rate into DNA. EXPERIMENTAL PROCEDURES MaterialsChemicals were from the same sources as previously described [8]. All 14C-labeled deoxyribonucleosides were from the Radiochemical Centre (Amersham, Buckinghamshire, England) and all were uniformly labeled except thymidine, which was labeled at C-2. Glass filters were Whatman GF81. XtrainsAll bacterial strains were derivatives of E . coli R .Thcir origins are given in Table 1. The symbols cdd, add, pup, and tpp refer t o loss of cytidine deaminase, adenosine deaminase, purine nucleoside phosphorylase, and thymidine phosphorylase, respectively. The mutation tZr-4 (thymine low requirement) [ill probably affects deoxyribose I ,5-phosphate mutase as it does not cause sensitivity t o deoxyribosides /12,13].

In vitro activities of nucleoside analog antiviral agents against salmonellae

“…ddC undergoes initial phosphorylation by deoxycytidine kinase (4,36). Deoxycytidine and deoxyguanosine kinase activities have not been detected for E. coli or salmonellae (16,28,29). The monophosphorylation of ACV to ACV-monophosphate requires virally specified thymidine kinase.…”

The determination of 5‐azapyrimidines and their derivatives in bacterial RNA

“…The strain E. coli OK 408, deficient in cytidine deaminase, was isolated by Karlstr(im [8] . E. coli B was used as cytidine-deaminase plus strain.…”

One-pot process of 2′-deoxyguanylic acid catalyzed by a multi-enzyme system

“…dNKs are not distributed in every organism. For example, only thymidine kinase (TKase) activity has been detected in E. coli, and neither deoxycytidine kinase (dCKase), deoxyguanosine kinase (dGKase) nor deoxyadenosine kinases (dAKase) activity was detected [14]. However, in Bacillus subtilis, in addition to TKase, there are two homodimeric dNKs, dGKase, which is highly specific for dGR, and dAKase/dCKase with high specificity for both deoxyadenosine (dAR) and deoxycytidine (dCR), respectively [15,16].…”