Nucleotide excision repair

Nucleotide Excision Repair (pronunciation: noo-klee-o-tide ex-sizh-un re-pair) is a DNA repair mechanism that involves the removal and replacement of damaged nucleotides in the DNA molecule.

Etymology

The term "Nucleotide Excision Repair" is derived from the process it describes. A nucleotide is the basic building block of DNA and RNA, and excision refers to the act of cutting out or removing something. In this context, it refers to the removal of damaged nucleotides from the DNA molecule.

Process

Nucleotide Excision Repair is a multi-step process that begins with the recognition of a damaged nucleotide by a set of proteins known as the DNA damage recognition complex. This complex then recruits other proteins to the site of damage, including an enzyme known as DNA helicase that unwinds the DNA double helix. This is followed by the excision of the damaged nucleotide by an enzyme known as endonuclease, and the gap left behind is filled by a DNA polymerase using the undamaged strand as a template. The process is completed by the action of a DNA ligase that seals the newly synthesized DNA into the existing DNA molecule.

Related Terms

• DNA repair
• Nucleotide
• DNA damage recognition complex
• DNA helicase
• Endonuclease
• DNA polymerase
• DNA ligase

See Also

• Base Excision Repair
• Mismatch Repair
• Direct Repair

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