title: Bacteriophage T7 deoxyribonucleic acid replication invitro. Bacteriophage T7 DNA polymerase: an an emzyme composed of phage- and host-specific subunits.
abstract: The DNA polymerase induced after infection of Escherichia coli by phage T7 has been purified 500-fold to near homogeneity as judged by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate.  The purified enzyme complements extracts of cells infected with a T7 gene 5 mutant to permit cell-free replication of duplex T7 DNA.  In contrast, purified T4 DNA polymerase or E. coli DNA polymerase I is unable to do so, thus suggesting a specific requirement for the T7 enzyme in the replication of the viral DNA.  E. coli TsnC protein is present in purified T7 DNA polymerase in one-to-one stoichiometry with T7 gene 5 protein, and can be isolated in homogeneous form from heat-denatured enzyme by chromatography on DEAE-cellulose.  The inactive form of T7 gene 5 protein that accumulates in tsnC hosts has been partially purified.  When partially purified gene 5 protein is mixed with purified TsnC protein, DNA polymerase activity is restored, and formation of a one-to-one complex between the two proteins occurs.  These results indicate that the functional form ofT7 DNA polymerase is a complex composed of phage- and host-specified subunits.
mesh_terms: D001426:Bacterial Proteins / Q000494:pharmacology; D002846:Chromatography, Affinity; D002848:Chromatography, DEAE-Cellulose; D003090:Coliphages / Q000378:metabolism*; D004254:DNA Nucleotidyltransferases / Q000302:isolation & purification / Q000378:metabolism*; D004261:DNA Replication; D003854:Deoxyribonucleotides / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000378:metabolism*; D009154:Mutation; D012967:Sodium Dodecyl Sulfate; D013879:Thioredoxins / Q000494:pharmacology
chemical_list: D001426:Bacterial Proteins; D003854:Deoxyribonucleotides; D012967:Sodium Dodecyl Sulfate; D013879:Thioredoxins; D004254:DNA Nucleotidyltransferases