Search results
Results From The WOW.Com Content Network
DNA polymerase I (or Pol I) is an enzyme that participates in the process of prokaryotic DNA replication. Discovered by Arthur Kornberg in 1956, [1] it was the first known DNA polymerase (and the first known of any kind of polymerase). It was initially characterized in E. coli and is ubiquitous in prokaryotes.
The Klenow fragment is a large protein fragment produced when DNA polymerase I from E. coli is enzymatically cleaved by the protease subtilisin.First reported in 1970, [1] it retains the 5' → 3' polymerase activity and the 3’ → 5’ exonuclease activity for removal of precoding nucleotides and proofreading, but loses its 5' → 3' exonuclease activity.
In prokaryotes, the FEN enzyme is found as an N-terminal domain of DNA polymerase I, but some prokaryotes appear to encode a second homologue. [ 1 ] [ 2 ] [ 3 ] The endonuclease activity of FENs was initially identified as acting on a DNA duplex which has a single-stranded 5' overhang on one of the strands [ 4 ] (termed a "5' flap", hence the ...
DNA polymerase's rapid catalysis due to its processive nature. Processivity is a characteristic of enzymes that function on polymeric substrates. In the case of DNA polymerase, the degree of processivity refers to the average number of nucleotides added each time the enzyme binds a template.
An evolutionary divergence (about 0.25 to 1.2 billion years ago), appears to have been associated with the separation of the DNA polymerase gene function from the 3’ to 5’ exonuclease editing gene function in the lineage that led to E. coli and S. typhimurium.
The polymerase is a monomeric protein with two distinct functional domains. Site-directed mutagenesis experiments support the proposition that this protein displays a structural and functional similarity to the Klenow fragment of the Escherichia coli Polymerase I enzyme; [3] it comprises a C-terminal polymerase domain and a spatially separated N-terminal domain with a 3'-5' exonuclease activity.
Nick translation [1] (or head translation), developed in 1977 by Peter Rigby and Paul Berg, is a tagging technique in molecular biology in which DNA polymerase I is used to replace some of the nucleotides of a DNA sequence with their labeled analogues, creating a tagged DNA sequence which can be used as a probe in fluorescent in situ hybridization (FISH) or blotting techniques.
Taq polymerase exonuclease is a domain found in the amino-terminal of Taq DNA polymerase I (thermostable). It assumes a ribonuclease H-like motif . The domain confers 5' -3' exonuclease activity to the polymerase.