What is the function of DNA glycosylase during base excision repair?

• A. Addition of the correct nucleotide.
• B. Cleavage of the phosphodiester bond.
• C. Addition of the correct nucleobase.
• D. Removal of the incorrect nucleotide.
• E. Removal of the incorrect nucleobase.

Answer: (E)

Verified step by step guidance

1. Understand the context of base excision repair (BER), which is a cellular mechanism that repairs damaged DNA throughout the cell cycle. It is primarily responsible for removing small, non-helix-distorting base lesions from the genome.
2. Identify the role of DNA glycosylase in the BER pathway. DNA glycosylases are a family of enzymes involved in the first step of base excision repair.
3. Recognize that DNA glycosylases are responsible for identifying and removing damaged or incorrect bases from DNA. They do this by cleaving the N-glycosidic bond between the base and the sugar-phosphate backbone, leaving an abasic site.
4. Clarify that the removal of the incorrect nucleobase by DNA glycosylase is crucial because it initiates the repair process, allowing other enzymes to further process the abasic site and restore the correct DNA sequence.
5. Conclude that the specific function of DNA glycosylase during base excision repair is the removal of the incorrect nucleobase, which is the first and essential step in correcting DNA damage.