What enzyme seals the nucleotide into its space during base excision repair (BER)?

Base excision repair (BER) is a critical cellular mechanism that corrects DNA damage, particularly from minor modifications such as single-base alterations, including deamination and oxidation. In the BER pathway, after a damaged base is recognized and removed by a DNA glycosylase, the remaining sugar phosphate backbone is then processed. This includes the action of DNA polymerase, which fills in the gap with the correct nucleotide after the removal of the damaged section.

However, the essential step that follows the insertion of the new nucleotide is the sealing of the sugar-phosphate backbone. This is where DNA ligase plays a pivotal role. DNA ligase is responsible for forming a phosphodiester bond between the newly inserted nucleotide and the adjacent nucleotide, effectively sealing the DNA strand and restoring its integrity.

This makes DNA ligase the correct answer when identifying the enzyme that seals the nucleotide into its place during the base excision repair process. The contribution of this enzyme is vital for the completion of the repair and the maintenance of genomic stability.