뉴클레오타이드 절제복구

Exposure of DNA to ultraviolet light and certain chemical carcinogens can cause a bulky lesion. A specific distortion of its normal structure. This type of damage can be fixed by a process called nucleotide excision repair.

The process begins when an enzyme complex, shown here in E. coli, containing the proteins UvrA and UvrB, travels along the DNA and detects the physical aberration of the lesion.

At that location the strands are separated and endonuclease enzymes such as UvrC cleave the strand on both sides of the damage. The enzyme DNA helicase then removes the cut pieces.

Another enzyme, DNA polymerase fills the gap with new nucleotides. Finally, the enzyme DNA ligase seals the edges between the new and old DNA completing the repair.