In this presentation, i have told about the basic function of DNA polymerase enzyme.

1. DNA POLYMERASE
By- Robin Singh

2. CONTENT
 WHAT IS DNA POLYMERASE
 HISTORY
 FUNCTION
 STRUCTURE

3. DNA POLYMERASE
■ DNA polymerase is an enzymethat
synthesizes DNA molecules from deoxyribonucleotides, the
building blocks of DNA.
■ These enzymes are essential for DNA replication and usually
work in pairs to create two identical DNA strands from a single
original DNA molecule.
■ During this process, DNA polymerase "reads" the existing DNA
strands to create two new strands that match the existing ones.
■ DNA polymerase adds nucleotides to the three prime (3')-end of
a DNA strand, one nucleotide at a time.

4. HISTORY
 In 1956, Arthur Kornberg and colleagues discovered DNA polymerase I (Pol I), in Escherichia coli.
 They described the DNA replication process by which DNA polymerase copies the base sequence of a
template DNA strand.
 Kornberg was later awarded the Nobel Prize in Physiology or Medicine in 1959 for this work.
 DNA polymerase II was also discovered by Thomas Kornberg (the son of Arthur Kornberg) and
Malcolm E. Gefter in 1970 while further elucidating the role of Pol I in E. coli DNA replication

5. FUNCTION
 to synthesize DNA from deoxyribonucleotides, the building blocks of
DNA.
 adds new, free nucleotides to the 3’ end of the newly-forming strand,
elongating it in a 5’ to 3’direction.
 DNA polymerase corrects the mistakes in the newly-synthesized DNA
by proofreading the newly-made strands.
 When an incorrect coupling is recognized, the DNApolymerase
reverses its direction by one base pair of DNA.
 he incorrect base pair is then excised and DNA polymerase tries to re-
insert the correct nucleotide before continuing forwards.

6. DNA POLYMERASE STRUCTURE
• The known DNA polymerases have highly conserved structure, which means that their overall
catalytic subunits vary very little from species to species, independent of their domain
structures.
• Conserved structures usually indicate important, irreplaceable functions of the cell, the
maintenance of which provides evolutionary advantages.
• The shape can be described as resembling a right hand with thumb, finger, and palm
domains.
• The palm domain appears to function in catalyzing the transfer of phosphoryl groups in the
phosphoryl transfer reaction. DNA is bound to the palm when the enzyme is active.
• The finger domain functions to bind the nucleoside triphosphates with the template base.
• The thumb domain plays a potential role in the processivity, translocation, and positioning of
the DNA.

8. Family Types of DNA polymerase Species Examples
A
Replicative and Repair
Polymerases
Eukaryotic and Prokaryotic
T7 DNA polymerase, Pol I, and
DNA Polymerase γ
B
Replicative and Repair
Polymerases
Eukaryotic and Prokaryotic Pol II, Pol B, Pol ζ, Pol α, δ, and
ε
C Replicative Polymerases Prokaryotic Pol III
D Replicative Polymerases Euryarchaeota Not well-characterized
X
Replicative and Repair
Polymerases
Eukaryotic
Pol β, Pol σ, Pol λ, Pol μ,
and Terminal
deoxynucleotidyl transferase
Y
Replicative and Repair
Polymerases
Eukaryotic and Prokaryotic Pol ι
[
(
1
i
5
o
]
ta),Pol κ (kappa), Pol η
(eta), Pol IV, and Pol V
RT
Replicative and Repair
Polymerases
Viruses, Retroviruses, and
Eukaryotic
Telomerase, Hepatitis B virus