Accuracy of DNA primase.
The base-pairing fidelity of DNA primase from calf thymus was studied in vitro by using a misinsertion assay based on synthetic polydeoxynucleotide templates. With poly(dT) as template, GMP misinsertions occurred with a frequency of one error per 1600 correctly incorporated nucleotides, while UMP and CMP were inserted with a frequency of 1/300 and 1/500, respectively. Accuracy with poly(dC, dT) as template was 1/200 for the misinsertion of UMP, and 1/300 for the misinsertion of CMP. Thus, DNA primase is the least accurate polynucleotide-synthesizing enzyme known. The results are discussed in terms of an obvious necessity for a priming mechanism at the beginning of DNA synthesis.
Zhang
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Max-Planck-Institute for Experimental Medicine, Department of Chemistry, Göttingen, F.R.G.
Grosse
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D000818:Animals; D002417:Cattle; D019915:DNA Primase; D004261:DNA Replication / Q000502:physiology*; D011071:Poly T / Q000378:metabolism; D011089:Polydeoxyribonucleotides / Q000378:metabolism; D012316:RNA Nucleotidyltransferases / Q000378:metabolism*; D013698:Templates, Genetic
D011089:Polydeoxyribonucleotides; D011071:Poly T; C045717:poly d(C-T); D019915:DNA Primase; D012316:RNA Nucleotidyltransferases