Nuclease Activity in a Fragment of Bacteriophage T4 Deoxyribonucleic Acid Polymerase Induced by the Amber Mutant am B22

摘要: Abstract T4 bacteriophage mutant am B22 (gene 43), an amber in the gene for DNA polymerase, produces a protein which lacks polymerase but retains nuclease function of wild type enzyme. The is shown to be fragment by comparing tryptic peptides two proteins. and enzymes each consist single polypeptide chain. molecular weight enzyme consistent with position mutation within gene. only other 43 mutants producing similar map at or very close site mutation. Both are exonucleases hydrolyze denatured from 3' terminus random rather than processive fashion. differs its markedly decreased affinity oligonucleotides. A higher concentration deoxynucleoside triphosphates required inhibit activity will not polymerize deoxynucleotides under any conditions have been tested.