title: Structure-function studies of the bacteriophage T4 DNA polymerase. Isolation of a novel suppressor mutant.
abstract: We describe here our first attempt in using suppressor mutations to study structure-function relationships of the bacteriophage T4 DNA polymerase. One intragenic suppressor mutation, J5(43) degrees, was isolated that suppresses the temperature sensitivity but not the mutator activity of tsM19, a DNA polymerase mutant. Thus, the substituted amino acid induced by the tsM19 lesion decreases DNA polymerase fidelity, even if the temperature sensitivity has been corrected by a second amino acid substitution in the DNA polymerase polypeptide. The isolation, mapping and characterization of the J5(43) degrees mutation as well as the purification and characterization of the tsM19-J5(43) degrees mutant DNA polymerase are presented. The suppressor isolation procedure has general applicability for the selection of suppressor mutations of other T4 DNA polymerase mutator mutants.
mesh_terms: D000167:Acriflavine / Q000378:metabolism; D003434:Crossing Over, Genetic; D004259:DNA-Directed DNA Polymerase / Q000235:genetics* / Q000378:metabolism; D003851:Deoxyribonucleases / Q000378:metabolism; D004352:Drug Resistance, Microbial; D005814:Genes, Viral; D009154:Mutation; D013329:Structure-Activity Relationship; D013489:Suppression, Genetic; D013604:T-Phages / Q000201:enzymology / Q000235:genetics*; D013696:Temperature
chemical_list: D000167:Acriflavine; D004259:DNA-Directed DNA Polymerase; D003851:Deoxyribonucleases