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XPG I protein domain

Field	Value
Symbol	XPG_I
Name	XPG_I
image	PDB 1a77 EBI.jpg
caption	flap endonuclease-1 from Methanococcus jannaschii
Pfam	PF00867
Pfam_clan	CL0464
InterPro	IPR006086
PROSITE	PDOC00658
SCOP	1a77
CDD	cd09868

In molecular biology, the XPG-I is a protein domain found on Xeroderma Pigmentosum Complementation Group G (XPG) protein. The XPG protein is an endonuclease which repairs DNA damage caused by ultraviolet light (UV light). The XPG protein repairs DNA by a process called, Nucleotide excision repair. Mutations in the protein commonly cause Xeroderma Pigmentosum which often lead to skin cancer.

Function

The function of the internal XPG (XPG-I) domain contains many of cysteine and glutamate amino acid residues that are frequently found in various enzyme active sites, DNA nucleases. The I domain, together with the N-terminal forms the catalytic domain that contains the active site.

Mechanism

XPG cleaves the 5'-overhanging flap structure that is generated when DNA polymerase encounters the 5'-end of a downstream Okazaki fragment. It has both 5'endo-/exonuclease and 5'-pseudo-Y-endonuclease activities. Cleaves the junction between single and double-stranded regions of flap DNA. The endonuclease binds 2 magnesium ions per subunit, which probably participate in the reaction catalyzed by the enzyme. May bind an additional third magnesium ion after substrate binding.

References

(1994). "Isolation of active recombinant XPG protein, a human DNA repair endonuclease.". J Biol Chem.
Clarkson SG. (2003). "The XPG story.". Biochimie.

Wikipedia Source

This article was imported from Wikipedia and is available under the Creative Commons Attribution-ShareAlike 4.0 License. Content has been adapted to SurfDoc format. Original contributors can be found on the article history page.

protein-families protein-domains dna-repair

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