DNA Polymerase is a member of the enzyme family that can duplicate genetic information which is saved in the nucleic acid DNA. This enables the generation of a faithful copy. DNA Polymerase helps to catalyze the synthesis of DNA molecules from nucleoside triphosphates. These are the molecular precursors of DNA.
As a result of this, they help to duplicate the complete genome of any living being before the process of division of a cell. They are also essential to maintain the wholeness of the genetic information during the lifespan of a cell. All living beings, that make use of the DNA for genetic information need some kind of DNA Polymerase to be able to survive. Living being could either be unicellular or pluricellular but they all need one or more DNA polymerases to live.
There are various types of DNA Polymerase. The various types are depending on the different functions that these DNA Polymerases perform. The most common kinds of DNA Polumeraese are 1 and 3.
DNA Polymerase 1 vs 3
The main difference between DNA Polymerase 1 and 3 is that DNA Polymerase 1 is vital to replicate the DNA. It is also commonly also known as Pol 1. On the other hand, DNA Polymerase 3 is vital for prokaryotic DNA replication. It is commonly also known as the holoenzyme.
Comparison Table Between DNA Polymerase 1 and 3
| Parameter of Comparison | DNA Polymerase 1 | DNA Polymerase 3 |
| Main Function | The main function of DNA Polymerase 1 is the replication of the DNA. | The main function of DNA Polymerase 3 is prokaryotic DNA replication. |
| Discovered by | DNA Polymerase 1 was discovered by Arthur Kornberg. | Thomas Kornberg and Malcolm Gefter had discovered DNA Polymerase. |
| Discovered In | DNA Polymerase 1 was discovered in 1956. | DNA Polymerase 3 was discovered in 1970. |
| Also Known as | DNA Polymerase 1 is also known as Pol 1. | DNA Polymerase 3 is also known as Holoenzyme. |
| Encoding process | The encoding process of DNA Polymerase 1 is done by polyA gene. | The encoding process of DNA Polymerase 3 is done by dnaE, dnaQ, and holE genes. |
| Family | DNA Polymerase 1 falls under family A. | DNA Polymerase 3 falls under family C. |
| RNA Primer | The RNA Primer is removed by the DNA Polymerase 1. | The RNA Primer is required by the DNA Polymerase to synthesize the DNA. |
| DNA Synthesis | The rate of DNA Synthesis of DNA Polymerase 1 is the addition of 10 to 20 nucleotides per second. | The rate of DNA Synthesis of DNA Polymerase 3 is the addition of round 1000 nucleotides per second. |
What is DNA Polymerase 1?
DNA Polymerase 1 is a common type of DNA Polymerase which has the polymerization and proofreading activity. It was discovered in 1956 by Arthur Kornberg. It is encoded by the polA gene. The DNA Polymerase 1 is used to replicate the DNA. It helps in the process of synthesis of a new DNA strand. The DNA Polymerase 1 also helps in filling gaps, repairing and recombining.
While replicating the DNA, the RNA primer is filled in the lagging strand of the DNA. The RNA primer is removed by the DNA Polymerase 1. It also helps to fill in the nucleotides that are essential to form the DNA in the direction 5’ to 3’. The rate at which DNA Polymerase 1 synthesis the DNA is about adding 10 to 20 nucleotides per second.
What is DNA Polymerase 3?
The DNA Ploymerase 3 is one of the main enzymes that is essential in replicating the prokaryotic DNA. It is required to pair the incoming nucleotides with the template strand. DNA Polymerse 3 also helps to proofread the DNA that has been replictated. It reads the newly added nucleotides of the template strand and if any mismatches are known, the DNA Polymerase removes it ansd then synthesis it again. It helps to keep the overall stability of the genome
The DNA Polymerase 3 was discovered in 1970 by Thomas Kornberg and Malcolm Gefter. It is also commonly known as Holoenzyme. It belongs to the Family C or Type C of the DNA Polymerase. The DNA Polymerase 3 has a 3′-5′ exonuclease activity.
Main Differences Between DNA Polymerase 1 and 3
- DNA Polymerase 1 is essential for the replication of DNA while on the other hand DNA Polymerase 3 is essential for prokaryotic DNA replication.
- DNA Polymerase 1 was first discovered in 1956 while on the other hand, DNA Polymerase 3 was first discovered in 1970.
- DNA Polymerase 1 was discovered by Arthur Kornberg. On the other hand, DNA Polymerase 3 was discovered by Thomas Kornberg and Malcolm Gefter.
- DNA Polymerase 1 is also commonly known as Pol 1, while on the other hand DNA Polymerase 3 is also commonly known as Holoenzyme.
- DNA Polymerase 1 belongs to DNA Polymerase family A while on the other hand DNA Polymerase 3 belongs to the family C of the DNA Polymerase.
- DNA Polymerase 1 removes the RNA primer while on the other hand, RNA primer is required by DNA Polymerase to synthesize the DNA.
- DNA Polymerase 1 acts on the lagging strand of the replication fork only, while on the other hand, DNA Polymerase 3 acts on the lagging strand as well as the leading strand of the replication fork.
Conclusion
The DNA Polymerase 1 and 3 are both two different kinds of DNA Polymerases that are essential in the prokaryotic DNA replication. Both of these have 5’ to 3’ polymerizing activity which in turn helps in proofreading of the DNA.
They also have an exonuclease activity. However, both the DNA Polymerase 1 and the DNA Polymerase 3 differ from each other as the main function of the DNA Polymerase 1 is to remove the RNA primer from 5’ to 3’ direction, while on the other hand the main function of the DNA Polymerase 3 is to add deoxyribonucleic acids to the 3’ end.
The DNA Polymerase 1 was first discovered in 1956 while on the other hand, DNA Polymerase 3 was first discovered in 1970.
References
- https://www.jbc.org/content/276/35/32411.short
- https://link.springer.com/article/10.1023/B:BIRY.0000029855.68502.fa