Dna Polymerase 3 Functions

Before replication can take place an enzyme called helicase unwinds the dna molecule from its tightly woven form in the process breaking the hydrogen bond. Each enzyme replicates one of the two strands that comprise the dna double helix.

Dna Replication And Types Of Dna

Polymerase function during dna replication dna polymerase enzymes typically work in a pairwise fashion.

Dna polymerase 3 functions. The holoenzyme apoenzyme protein part coenzyme holoenzyme functions as a heterodimer of complexes at the replication fork with each monomer seeing to the synthesis of one daughter strand. Dna polymerase iii will then synthesize a continuous or discontinuous strand of dna depending if this is occurring on the leading or lagging strand okazaki fragment of the dna. Dna polymerase 3 possesses 5 to 3 polymerization activity where new nucleotides are added to the growing chain at its 3 end.

The main function of the third polymerase pol iii is duplication of the chromosomal dna while other dna polymerases are involved mostly in dna repair and translesion dna synthesis. The primary role of dna polymerases is to accurately and efficiently replicate the genome in order to ensure the maintenance of the genetic information and its faithful transmission through generations. The enzyme dna polymerase iii is the primary enzyme involved with bacterial dna replication.

Dna polymerase 3 is the main enzyme involved in prokaryotic dna replication. Every time a cell divides dna polymerases are required to duplicate the cell s dna so that a copy of the original dna molecule can be passed to each daughter cell. Dna polymerase iii is the principle replicative dna polymerase of e coli.

The dna polymerase iii holoenzyme is composed of 10 subunits. In this way genetic information is passed down from generation to generation. The enzyme aids the base pairing of incoming nucleotides with the template strand.

It performs the 5 3 polymerase function which means that it adds nucleotides to the 3 end of the forming dna strand during replication. Dna polymerase iii has a high processivity and therefore synthesizes dna very quickly. It is a multisubunit complex.

Together with a dna helicase and a primase pol iii he participates in the replicative apparatus that acts at the replication fork. Before replication can start the enzyme helicase unwinds the two dna strands. These enzymes cannot replace each other as both have different functions to be performed.

Dna polymerase adds nucleotides to the three prime end of a dna strand one nucleotide at a time. Both strands become templates for replication. α ε φ subunits core enzyme.

This is not a simple task considering the size of the genome and its constant exposure to endogenous and environmental dna damaging agents. Dna polymerase 3 is essential for the replication of the leading and the lagging strands whereas dna polymerase 1 is essential for removing of the rna primers from the fragments and replacing it with the required nucleotides. The core of the polymerase contains the catalytic polymerase subunit α the proofreading 3 5 exonuclease ε and a subunit of unknown function θ.

Pdf Dna Polymerase Iii Holoenzyme Structure And Function Of A