DNA polymerase 3′ → 5′ exonuclease activity: Different roles of the beta hairpin structure in family-B DNA polymerases

- T4 DNA polymerase proofreading requires a beta hairpin structure.
- Yeast DNA polymerase delta proofreading does not require the hairpin.
- The yeast DNA polymerase delta hairpin is needed for fitness.
- DNA polymerase evolution.
- Mismatch repair regulates the checkpoint when DNA pol delta replication is hindered.