Eukaryotic and Prokaryotic DNA Polymerase
DNA polymerases are a group of enzymes that are used to make copies of DNA
templates, essentially used in DNA replication mechanisms. These enzymes
make new copies of DNA from existing templates and also function by
repairing the synthesized DNA to prevent mutations. DNA polymerase
catalyzes the formation of the phosphodiester bond which makes up the
backbone of DNA molecules. It uses a magnesium ion in catalytic activity to
balance the charge from the phosphate group.
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What are DNA polymerases?
DNA polymerase was first identified by Arthur Kornberg in lysates
of Escherichia coli, in 1956.
The enzyme is found and used in the DNA replication of both prokaryotic and
eukaryotic cells.
Several types of DNA polymerase enzymes have been discovered with the
first one to be discovered named DNA polymerase I.
Each of these types plays a major role in replication and DNA repair
mechanisms.
However, DNA polymerases are not used for initiating the synthesis of new
strands, but in the extension of already existing DNA or RNA strands which
are paired with a template strand.
DNA polymerase starts its mechanism after a short RNA fragment is known
as a primer is created and paired with a template DNA strand.
, DNA polymerase acts by synthesizing the new DNA strand by adding new
nucleotides that match those of the template, extending the 3′ end of the
template chain. Each nucleotide is linked with a phosphodiester bond.
The DNA polymerase uses energy from the hydrolysis of the
phosphoanhydride bond that is between the three phosphates (nucleoside
triphosphates) attached to each free base (nucleotides).
The addition of a nucleotide to a growing DNA strand forms a phosphodiester
bond between the phosphate of the nucleotide to the growing chain using the
high-energy phosphate bond of hydrolysis, releasing two distal phosphates
known as pyrophosphate.
DNA polymerases are very accurate in their mechanism with minimal errors
of less than one error for every 107 nucleotides.
Some types of DNA polymerase have the ability to proofread and remove
unmatched bases of nucleotides and correct them.
They also correct post-replication mismatches by monitoring and repairing the
errors, by distinguishing mismatches of the new strand from the template
strand sequences.
The eukaryotic cell contains five DNA polymerase α, β, γ, δ, and ε.
Polymerase γ is found in the cell mitochondria and it actively replicates the
mitochondrial DNA, while polymerase α, β, δ are found in the cell nucleus
hence are involved in the nuclear DNA replication.
Polymerase α and δ are majorly applied and active in diving cells hence
involved in replication while polymerase β is active in both diving and non-
dividing cells hence it is involved in the repair of DNA damage.
DNA polymerases are a group of enzymes that are used to make copies of DNA
templates, essentially used in DNA replication mechanisms. These enzymes
make new copies of DNA from existing templates and also function by
repairing the synthesized DNA to prevent mutations. DNA polymerase
catalyzes the formation of the phosphodiester bond which makes up the
backbone of DNA molecules. It uses a magnesium ion in catalytic activity to
balance the charge from the phosphate group.
Skip Ad
What are DNA polymerases?
DNA polymerase was first identified by Arthur Kornberg in lysates
of Escherichia coli, in 1956.
The enzyme is found and used in the DNA replication of both prokaryotic and
eukaryotic cells.
Several types of DNA polymerase enzymes have been discovered with the
first one to be discovered named DNA polymerase I.
Each of these types plays a major role in replication and DNA repair
mechanisms.
However, DNA polymerases are not used for initiating the synthesis of new
strands, but in the extension of already existing DNA or RNA strands which
are paired with a template strand.
DNA polymerase starts its mechanism after a short RNA fragment is known
as a primer is created and paired with a template DNA strand.
, DNA polymerase acts by synthesizing the new DNA strand by adding new
nucleotides that match those of the template, extending the 3′ end of the
template chain. Each nucleotide is linked with a phosphodiester bond.
The DNA polymerase uses energy from the hydrolysis of the
phosphoanhydride bond that is between the three phosphates (nucleoside
triphosphates) attached to each free base (nucleotides).
The addition of a nucleotide to a growing DNA strand forms a phosphodiester
bond between the phosphate of the nucleotide to the growing chain using the
high-energy phosphate bond of hydrolysis, releasing two distal phosphates
known as pyrophosphate.
DNA polymerases are very accurate in their mechanism with minimal errors
of less than one error for every 107 nucleotides.
Some types of DNA polymerase have the ability to proofread and remove
unmatched bases of nucleotides and correct them.
They also correct post-replication mismatches by monitoring and repairing the
errors, by distinguishing mismatches of the new strand from the template
strand sequences.
The eukaryotic cell contains five DNA polymerase α, β, γ, δ, and ε.
Polymerase γ is found in the cell mitochondria and it actively replicates the
mitochondrial DNA, while polymerase α, β, δ are found in the cell nucleus
hence are involved in the nuclear DNA replication.
Polymerase α and δ are majorly applied and active in diving cells hence
involved in replication while polymerase β is active in both diving and non-
dividing cells hence it is involved in the repair of DNA damage.
