Nucleotide kinase that catalyzes the phosphorylation of dGMP and dTMP to dGDP and dTDP (PubMed:18599435, PubMed:20497505). A double mutation in this protein and the RecBCD inhibitor gp5.9 protein allow phage to overcome the retron Ec48 bacteriophage defense system. This protein alone when overexpressed in E.coli does not cause growth arrest; Y128C may be a silent mutation (PubMed:33157039). Dodecamer. Produced by alternative initiation at Met-42 of isoform Small gp1.7.