Endonuclease VII of phage T4 triggers mismatch correction in vitro.
The reactivity of endonuclease VII (gp49 of phage T4) with DNA-loops of eight, four, or one nucleotide, or any of 12 possible base mismatches was tested in vitro. Endonuclease VII introduces double-strand breaks by nick and counter-nick within six nucleotides 3' from the mispairings. High relative cleavage efficiencies at mismatches in heteroduplexes correlate with their decreased thermal stability and vice versa. A delay between nick and counter-nick was sufficient to allow T4 DNA-polymerase and T4 DNA-ligase to correct a C/C-mismatch in vitro, thereby saving the DNA from double-strand breakage. Very short repair tracks of three to four nucleotides mapped between the mismatch and one of the formerly induced nicks, which were subsequently sealed by DNA ligase.
Solaro
P C
PC
Institute for Genetics, University of Cologne, Köln, Germany.
Birkenkamp
K
K
Pfeiffer
P
P
Kemper
B
B
D017122:Bacteriophage T4 / Q000201:enzymology* / Q000235:genetics*; D001482:Base Composition; D001483:Base Sequence; D004260:DNA Repair; D004279:DNA, Viral / Q000235:genetics / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D004706:Endodeoxyribonucleases / Q000378:metabolism*; D004795:Enzyme Stability; D008969:Molecular Sequence Data; D009692:Nucleic Acid Heteroduplexes / Q000138:chemical synthesis / Q000378:metabolism; D009838:Oligodeoxyribonucleotides; D016133:Polymerase Chain Reaction; D013696:Temperature
D004279:DNA, Viral; D009692:Nucleic Acid Heteroduplexes; D009838:Oligodeoxyribonucleotides; D004706:Endodeoxyribonucleases; C035571:endodeoxyribonuclease VII