The accuracy of DNA polymerase activity is subject to a 3′ exonucleolytic proofreading step. Which of the following statements is true?
- The polymerase and exonuclease site are physically close to each other.
- The 3′ exonuclease has very high specificity for mismatched pairs.
- The K M for DNA polymerase for chain extension from a mismatch is about 3 orders of magnitude higher, allowing the mismatch to reach the exonuclease site.
- All of the listed statements are true.