What is the structure of DNA polymerase?
The basic structure of all DNA polymerases consists of subdomains referred to as the palm, fingers, and thumb and resemble an open right hand. The palm contains catalytically essential amino acids in it’s active sites. The fingers are essential for nucleotide recognition and binding.
What DNA polymerase do prokaryotes have?
In prokaryotes, three main types of polymerases are known: DNA pol I, DNA pol II, and DNA pol III. It is now known that DNA pol III is the enzyme required for DNA synthesis; DNA pol I and DNA pol II are primarily required for repair.
How many DNA polymerase are in prokaryotes?
five different DNA polymerases
Prokaryotes contain five different DNA polymerases named from I to V. DNA polymerase III – is the main enzyme responsible for replication. Other DNA polymerases take part in repair, removing, primer, proofreading, translesion synthesis. Eukaryotes also contain many different types of DNA polymerase.
Why is DNA polymerase used in prokaryotes?
The physiological function of Pol I is mainly to support repair of damaged DNA, but it also contributes to connecting Okazaki fragments by deleting RNA primers and replacing the ribonucleotides with DNA….
|DNA polymerase I
|genome: 4.04 – 4.05 Mb
Which of the three prokaryotic polymerase is used in proofreading?
In bacteria, all three DNA polymerases (I, II and III) have the ability to proofread, using 3′ → 5′ exonuclease activity.
How does DNA polymerase structure relate to its function?
The DNA polymerases generally have a conserved structure, and therefore, defining its vital role in the cell function which can not be replaced. DNA polymerases are made up of subdomains resembling an open right hand as palm, fingers, and thumb. The palm contains the catalytic essential amino acids in its active sites.
What are the three types of DNA polymerase?
Classification. On the basis of sequence similarities, DNA polymerases can fall into three groups: type A, type B and type C, which have homology to polA (pol I), polB (pol II) and polC (pol III) from Escherichia coli, respectively [1,2].
What is the rule of DNA polymerase?
The DNA polymerase moves along the DNA (or RNA) template, extending the primer in the 5′ → 3′ direction according to the Watson–Crick base pairing rule, i.e., A pairs with T (or U) and C pairs with G (see Section II, Chapter 1).
How does DNA replication in prokaryotes?
Replication in prokaryotes starts from a sequence found on the chromosome called the origin of replication—the point at which the DNA opens up. Helicase opens up the DNA double helix, resulting in the formation of the replication fork.
Do prokaryotes have multiple DNA polymerases?
Prokaryotes contain five different types of DNA polymerase.