On the fidelity of DNA replication. Isolation of high fidelity DNA polymerase-primase complexes by immunoaffinity chromatography.
Error rates for conventionally purified DNA polymerase-alpha from calf thymus, chicken, and human sources have been reported to be one in 10,000 to one in 40,000 nucleotides incorporated. Isolation of polymerase-alpha by immunoaffinity chromatography yields a multiprotein high molecular weight replication complex that contains an associated DNA primase (Wong, S. W., Paborsky, L. R., Fisher, P. A., Wang, T. S-F., and Korn, D. (1986) J. Biol. Chem. 261, 7958-7968). We have isolated DNA polymerase-primase complexes from calf thymus, from a human lymphoblast cell line (TK-6), and from Chinese hamster lung cells (V-79) using two different methods of immunoaffinity chromatography. These enzyme complexes are 12- to 20-fold more accurate than conventionally purified calf thymus DNA polymerase-alpha when assayed using the phi X174am3 fidelity assay; estimated error rates are one in 460,000 to one in 830,000 nucleotides incorporated when the enzyme complex is freshly isolated. The polymerase-primase complex from calf thymus exhibited no detectable 3'----5' exonuclease activity using a heteroduplex substrate containing a single 3'-terminal mismatched nucleotide. Upon prolonged storage at -70 degrees C, the error rate of the immunoaffinity-purified calf thymus DNA polymerase-primase complex increases to about one in 50,000 nucleotides incorporated, an error rate similar to that exhibited by conventional isolates of DNA polymerase-alpha.
D000818:Animals; D010584:Bacteriophage phi X 174 / Q000235:genetics; D002417:Cattle; D002460:Cell Line; D002846:Chromatography, Affinity; D006224:Cricetinae; D019915:DNA Primase; D004261:DNA Replication; D004279:DNA, Viral / Q000096:biosynthesis; D004330:Drosophila / Q000201:enzymology; D004355:Drug Stability; D005092:Exonucleases / Q000378:metabolism; D006801:Humans; D007159:Immunologic Tests; D008168:Lung / Q000201:enzymology; D008214:Lymphocytes / Q000201:enzymology; D012316:RNA Nucleotidyltransferases / Q000302:isolation & purification* / Q000378:metabolism; D013950:Thymus Gland / Q000201:enzymology
D004279:DNA, Viral; D019915:DNA Primase; D012316:RNA Nucleotidyltransferases; D005092:Exonucleases