Final answer:
Mismatched bases during DNA replication can be corrected by mismatch repair mechanisms, where DNA polymerase excises incorrect nucleotides and replaces them with correct ones, utilizing methylation patterns in bacteria to distinguish between the parental and daughter strands.
Step-by-step explanation:
During kinetic proofreading, which is a part of the DNA replication process, the DNA polymerase enzyme performs a vital proofreading function. If a mismatched base is incorporated into the DNA strand, DNA polymerase utilizes its 3' exonuclease activity to excise the incorrect nucleotide. After this mismatch repair mechanism, the correct base is inserted.
In E. coli, mismatch repair proteins identify the newly synthesized DNA strand by distinguishing it from the parental strand based on methylation patterns. The parental DNA strand is methylated, whereas the daughter strand is not, which is known as hemimethylation. Repair enzymes, including MutS, MutL, and MutH, recognize these methylation cues to excise the incorrect nucleotide.