T7 DNA polymerase
Encyclopedia
The T7 DNA polymerase
of the T7
bacteriophage
is a DNA-dependent DNA polymerase responsible for the fast rate of T7 phage DNA replication in vivo. The polymerase consists of a 1:1 complex of the viral T7 gene 5 protein (80kDA) and the E. coli thioredoxin (12kDA).
It lacks a 5' -> 3' exonuclease domain, but the 3' -> 5' exonuclease activities are approximately 1000-fold greater than that of Klenow fragment
. The exonuclease activity appears to be responsible for the high fidelity of this enzyme and prevents strand displacement synthesis
This polymerase is unique due to its considerable processivity
, or ability to stay on DNA for a greater than average number of base pairs. It is also suitable for site-directed mutagenesis but is not recommended for DNA sequencing applications.
DNA polymerase
A DNA polymerase is an enzyme that helps catalyze in the polymerization of deoxyribonucleotides into a DNA strand. DNA polymerases are best known for their feedback role in DNA replication, in which the polymerase "reads" an intact DNA strand as a template and uses it to synthesize the new strand....
of the T7
T7 phage
Bacteriophage T7 is a bacteriophage capable of infecting susceptible bacterial cells. It infects most strains of Escherichia coli Bacteriophage T7 is a bacteriophage capable of infecting susceptible bacterial cells. It infects most strains of Escherichia coli Bacteriophage T7 is a bacteriophage...
bacteriophage
Bacteriophage
A bacteriophage is any one of a number of viruses that infect bacteria. They do this by injecting genetic material, which they carry enclosed in an outer protein capsid...
is a DNA-dependent DNA polymerase responsible for the fast rate of T7 phage DNA replication in vivo. The polymerase consists of a 1:1 complex of the viral T7 gene 5 protein (80kDA) and the E. coli thioredoxin (12kDA).
It lacks a 5' -> 3' exonuclease domain, but the 3' -> 5' exonuclease activities are approximately 1000-fold greater than that of Klenow fragment
Klenow fragment
right|thumb|450px|Functional domains in the Klenow Fragment and DNA Polymerase I .The Klenow fragment is a large protein fragment produced when DNA polymerase I from E. coli is enzymatically cleaved by the protease subtilisin...
. The exonuclease activity appears to be responsible for the high fidelity of this enzyme and prevents strand displacement synthesis
This polymerase is unique due to its considerable processivity
Processivity
In molecular biology, processivity is a measure of the average number of nucleotides added by a DNA polymerase enzyme per association/disassociation with the template. DNA polymerases associated with DNA replication tend to be highly processive, while those associated with DNA repair tend to have...
, or ability to stay on DNA for a greater than average number of base pairs. It is also suitable for site-directed mutagenesis but is not recommended for DNA sequencing applications.