About PCNA / Proliferating Cell Nuclear Antigen Protein:
Cell nuclear antigen protein PCNA is a DNA polymerase that helps initiate the synthesis of DNA. It also assists in both DNA repair and replication processes.
PCNA is a nucleotide-binding protein with three domains:
●An N-terminal region for ATP binding
●A middle part responsible for catalysis
●The C-terminus which binds to DNA
This enzyme can be in various locations throughout the cell, such as chromatin during mitosis or after UV irradiation.
Mechanism of PCNA
PCNA binds to the single-stranded DNA on one side and, with ATP present, it helps direct the second strand of DNA. PCNA also facilitates the removal of RNA primers in replication and is involved in maintaining fidelity during replication.
This protein is essential for genome stability and sensitivity to UV irradiation as well as for DNA repair.
Functions of Proliferating Cell Nuclear Antigen Protein
PCNA has an extensive range of functions in the cell and is involved with processes such as replication, transcription, recombination, and meiosis.
It helps maintain genome stability by repairing single-stranded breaks that can lead to mutations or rearrangements. Cells need an increased PCNA level when exposed to UV-light or cisplatin.
PCNA is a vital component of the DNA replication process; it interacts with the primase complex to form an elongating RNA primer and helps maintain fidelity during replication by removing RNA primers from newly synthesized strands of DNA before they copy.
It also assists in recombination reactions that produce genetic diversity, and it is involved in meiosis and mitosis.
In conclusion, PCNA is a protein that helps initiate the synthesis of DNA. It assists in both DNA repair and replication processes, as well as maintaining genome stability.