Which DNA polymerase has proofreading capabilities?

DNA Polymerase III is known for its proofreading capabilities. This enzyme plays a crucial role in DNA replication in prokaryotes and is responsible for synthesizing the new DNA strand. One of its key features is the presence of a 3' to 5' exonuclease activity, which allows it to remove incorrectly incorporated nucleotides. This proofreading mechanism significantly enhances the fidelity of DNA replication, reducing the frequency of mutations.

The other polymerases mentioned, such as DNA Polymerase I and DNA Polymerase II, have their own functions, including DNA repair and the removal of RNA primers, but they are not primarily responsible for the main DNA synthesis during replication. DNA Polymerase IV, while involved in DNA repair and prone to mistakes during synthesis, does not possess robust proofreading capabilities like DNA Polymerase III does. Understanding the specific roles and features of each polymerase helps clarify their distinct functions in cellular processes.