Final answer:
The enzyme that can proofread DNA using a 3-> 5 exonuclease activity is DNA polymerase III.
Step-by-step explanation:
The enzyme that can proofread DNA using a 3-> 5 exonuclease activity is DNA polymerase III.
Background:
DNA polymerase III is one of the key enzymes involved in DNA replication in bacteria. It has a 3-> 5 exonuclease activity, which allows it to remove nucleotides from the growing DNA strand when an incorrect base has been added. This proofreading ability helps to maintain the accuracy of DNA replication.
Example:
For example, if an incorrect base is added by mistake, DNA polymerase III can recognize this error and cut the phosphodiester bond between the incorrect base and the growing strand. It then replaces the incorrect nucleotide with the correct one before continuing with DNA synthesis.