title: DNA polymerase from mesophilic and thermophilic bacteria. III. Lack of fidelity in the replication of synthetic polydeoxyribonucleotides by DNA polymerase from Bacillus licheniformis and Bacillus stearothermophilus.
abstract: 1. DNA polymerase from the mesophile Bacillus licheniformis and the thermophile Bacillus stearothermophilus has been used to study the replication of poly(dA-dT)-poly(dA-dT) and poly(dC)-poly(dG) templates at 37, 45, and 55 degrees C. 2. Incorporation of non-complementary deoxyribonucleoside triphosphates (misincorporation) occurred with both enzymes and both templates. Non-specific incorporation (de novo polynucleotide synthesis, random attachment to existing strands, and tritium exchange of nucleotides) accounted for, at most, a small fraction of the total observed misincorporation. The error rates at 37 degrees C for the complete system were as follows:: B. licheniformis: dATP, 1/61; dCTP, 1/830; dGTP, 1/360; dTTP, 1/65; B. stearothermophilus: dATP, 1/68; dCTP, 1/1430; dGTP, 1/440; dTTP, 1/67. For both organisms, the error rate for dCTP and dGTP was independent of incubation temperature; the error rate for dATP and dTTP was 5-50-fold greater than that for dCTP or dGTP and increased significantly from 37 to 55 degrees C. 3. The ratio of dATP to dTTP incorporation with the poly(dA-dT)-poly-(dA-dT) template was independent of temperature and close to unity. The ratio of dCTP to dGTP incorporation with the poly(dC)-poly(dG) template decreased from approx. 0.2 to 0.05 for the mesophile and from approx. 0.06 to 0.03 for the thermophile as the temperature increased from 37 to 55 degrees C.
mesh_terms: D001407:Bacillus / Q000201:enzymology*; D004261:DNA Replication; D004259:DNA-Directed DNA Polymerase / Q000378:metabolism*; D001411:Geobacillus stearothermophilus / Q000201:enzymology*; D007700:Kinetics; D011089:Polydeoxyribonucleotides / Q000096:biosynthesis; D013045:Species Specificity; D013329:Structure-Activity Relationship; D013696:Temperature; D013698:Templates, Genetic
chemical_list: D011089:Polydeoxyribonucleotides; D004259:DNA-Directed DNA Polymerase