What is the purpose of nucleotide excision repair?

Nucleotide excision repair serves a crucial role in maintaining the integrity of the DNA by specifically targeting and removing bulky DNA adducts, which can disrupt the normal structure of the DNA helix. Among the most common types of damage that this repair mechanism addresses are thymine dimers, which are formed when two adjacent thymine bases covalently bond in response to ultraviolet (UV) radiation. This bonding distorts the DNA structure, leading to potential replication errors or other forms of genetic instability if left uncorrected.

The process involves several key steps: recognition of the distortion in the DNA, excision of the damaged segment, and subsequent resynthesis of the DNA segment using the undamaged strand as a template. This mechanism is vital for cellular protection and overall genomic stability, as it not only fixes specific types of DNA damage but also prevents mutations that could lead to diseases like cancer.

In contrast, the other options reflect different DNA repair mechanisms. For instance, the repair of single nucleotide errors is primarily handled by base excision repair, while double-strand breaks are typically addressed by homologous recombination or non-homologous end joining. The correction of errors in daughter strands after replication falls under mismatch repair. Thus, the primary function of nucleotide